MediumCVE-2026-55653

    Red Hat: Double Free (CVE-2026-55653)

    Published Last modified Sources: BSI, Red Hat, CVE.org, Msrc Update Guide

    Share

    What is affected, what to do

    A flaw was found in OpenSSH. A malicious SSH server can exploit a double free vulnerability in the Diffie-Hellman Group Exchange (DH-GEX) client path.

    An exploit is publicly available. Update Red Hat OpenShift AI 3.0 to version 1791818496, Red Hat Enterprise Linux 10 to version 0:9.9p1-25.el10_2, Red Hat Enterprise Linux 10.0 Extended Update Support to version 0:9.9p1-7.el10_0.5.

    Affected
    • Red Hat OpenShift AI 3.0 lt *..1791818496
    • Red Hat Enterprise Linux 10 lt *..0:9.9p1-25.el10_2
    • Red Hat Enterprise Linux 10.0 Extended Update Support lt *..0:9.9p1-7.el10_0.5
    • Red Hat Enterprise Linux 8 lt *..0:8.0p1-30.el8_10
    • Red Hat Enterprise Linux 9 lt *..0:9.9p1-9.el9_8
    • Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions lt *..0:8.7p1-30.el9_2.13
    • Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions lt *..0:8.7p1-38.el9_4.10
    • Red Hat Enterprise Linux 9.6 Extended Update Support lt *..0:8.7p1-45.el9_6.5
    • Red Hat Hardened Images lt *..10.3p1-6.hum1
    • Red Hat OpenShift AI 3.0 lt *..1791818590
    • Red Hat OpenShift AI 3.0 lt *..1791818589
    • Red Hat OpenShift AI 3.0 lt *..1791818505
    • Red Hat OpenShift AI 3.0 lt *..1791818502
    • Red Hat OpenShift AI 3.0 lt *..1793042072
    • Red Hat OpenShift AI 3.2 lt *..1791818602
    • Red Hat OpenShift AI 3.2 lt *..1791818598
    • Red Hat OpenShift AI 3.2 lt *..1791818512
    • Red Hat OpenShift AI 3.2 lt *..1791818587
    • Red Hat OpenShift AI 3.2 lt *..1791818778
    • Red Hat OpenShift AI 3.3 lt *..1791818782
    • Red Hat OpenShift AI 3.3 lt *..1791818627
    • Red Hat OpenShift AI 3.3 lt *..1791818790
    • Red Hat OpenShift AI 3.3 lt *..1791818874
    • Red Hat OpenShift AI 3.3 lt *..1791818792
    • Red Hat OpenShift AI 3.3 lt *..1791818662
    • Red Hat OpenShift AI 3.3 lt *..1791818877
    • Red Hat OpenShift AI 3.4 lt *..1791883722
    • Red Hat OpenShift AI 3.4 lt *..1791881612
    • Red Hat OpenShift AI 3.4 lt *..1791885618
    • Red Hat OpenShift AI 3.4 lt *..1791881487
    • Red Hat OpenShift AI 3.4 lt *..1791881732
    • Red Hat OpenShift AI 3.4 lt *..1791883315
    • Red Hat OpenShift AI 3.4 lt *..1791881486
    • Red Hat OpenShift AI 3.4 lt *..1791881769
    • Red Hat OpenShift AI 3.4 lt *..1791885505
    • Red Hat OpenShift AI 3.5 lt *..1791819252
    • Red Hat OpenShift AI 3.5 lt *..1791818749
    • Red Hat OpenShift AI 3.5 lt *..1791819206
    • Red Hat OpenShift AI 3.5 lt *..1791818979
    • Red Hat OpenShift AI 3.5 lt *..1791819123
    • Red Hat OpenShift AI 3.5 lt *..1791818901
    • Red Hat OpenShift AI 3.5 lt *..1791820333
    • Red Hat OpenShift AI 3.5 lt *..1791819495
    • Red Hat OpenShift AI 3.5 lt *..1791819104
    • Red Hat Update Infrastructure 5 lt *..1786435483
    • Red Hat Update Infrastructure 5 lt *..1786533529
    • Red Hat Update Infrastructure 5 lt *..1787135742
    • Red Hat Update Infrastructure 5 lt *..1787241260
    Fixed in
    • Red Hat OpenShift AI 3.0 1791818496
    • Red Hat Enterprise Linux 10 0:9.9p1-25.el10_2
    • Red Hat Enterprise Linux 10.0 Extended Update Support 0:9.9p1-7.el10_0.5
    • Red Hat Enterprise Linux 8 0:8.0p1-30.el8_10
    • Red Hat Enterprise Linux 9 0:9.9p1-9.el9_8
    • Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions 0:8.7p1-30.el9_2.13
    • Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions 0:8.7p1-38.el9_4.10
    • Red Hat Enterprise Linux 9.6 Extended Update Support 0:8.7p1-45.el9_6.5
    • Red Hat Hardened Images 10.3p1-6.hum1
    • Red Hat OpenShift AI 3.0 1791818590
    • Red Hat OpenShift AI 3.0 1791818589
    • Red Hat OpenShift AI 3.0 1791818505
    • Red Hat OpenShift AI 3.0 1791818502
    • Red Hat OpenShift AI 3.0 1793042072
    • Red Hat OpenShift AI 3.2 1791818602
    • Red Hat OpenShift AI 3.2 1791818598
    • Red Hat OpenShift AI 3.2 1791818512
    • Red Hat OpenShift AI 3.2 1791818587
    • Red Hat OpenShift AI 3.2 1791818778
    • Red Hat OpenShift AI 3.3 1791818782
    • Red Hat OpenShift AI 3.3 1791818627
    • Red Hat OpenShift AI 3.3 1791818790
    • Red Hat OpenShift AI 3.3 1791818874
    • Red Hat OpenShift AI 3.3 1791818792
    • Red Hat OpenShift AI 3.3 1791818662
    • Red Hat OpenShift AI 3.3 1791818877
    • Red Hat OpenShift AI 3.4 1791883722
    • Red Hat OpenShift AI 3.4 1791881612
    • Red Hat OpenShift AI 3.4 1791885618
    • Red Hat OpenShift AI 3.4 1791881487
    • Red Hat OpenShift AI 3.4 1791881732
    • Red Hat OpenShift AI 3.4 1791883315
    • Red Hat OpenShift AI 3.4 1791881486
    • Red Hat OpenShift AI 3.4 1791881769
    • Red Hat OpenShift AI 3.4 1791885505
    • Red Hat OpenShift AI 3.5 1791819252
    • Red Hat OpenShift AI 3.5 1791818749
    • Red Hat OpenShift AI 3.5 1791819206
    • Red Hat OpenShift AI 3.5 1791818979
    • Red Hat OpenShift AI 3.5 1791819123
    • Red Hat OpenShift AI 3.5 1791818901
    • Red Hat OpenShift AI 3.5 1791820333
    • Red Hat OpenShift AI 3.5 1791819495
    • Red Hat OpenShift AI 3.5 1791819104
    • Red Hat Update Infrastructure 5 1786435483
    • Red Hat Update Infrastructure 5 1786533529
    • Red Hat Update Infrastructure 5 1787135742
    • Red Hat Update Infrastructure 5 1787241260

    Not sure whether and how you are affected? Ask a question about this vulnerability

    Metrics

    6.5

    Priority

    XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

    Source: NVD, CVSS v3

    4.3

    CVSS v3

    Severity Medium on the scale from 0 to 10.

    Source: BSI, Red Hat, CVE.org, Msrc Update Guide

    0.5 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 44.8

    Show all metrics
    Severity
    Medium
    Priority (0–325)

    The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?

    Read in glossary
    56.70 Methodology
    Exploit maturity

    An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.

    Read in glossary
    PoC (publicly reported)
    XIEM Effective CVSS

    XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.

    Read in glossary
    6.5 Methodology
    CVSS v3

    CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.

    Read in glossary
    4.3
    EPSS score

    The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.

    Read in glossary
    0.5 %
    Low — model estimates < 1% exploitation likelihood.
    EPSS percentile

    The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.

    Read in glossary
    44.8
    High — this CVE ranks above the median of all CVEs scored today (rank ≥ 36%).
    KEV status

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    —
    Published
    CISA assessment (SSVC)
    Exploitation: none known · not automatable · Technical impact: partial
    Source: CISA Vulnrichment, as of 23 June 2026
    CWE

    CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.

    Read in glossary
    CWE-415

    Detection rules

    No NEOSEC detection rule is available for this vulnerability yet.

    Classification under NIS2 and CRA

    Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

    NIS2

    NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.

    Read in glossary
    Handle the vulnerability in regular vulnerability handling under Art. 21(2)(e) NIS2.
    CRA

    The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.

    Read in glossary
    From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
    ISO/IEC 27001

    ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.

    Read in glossary
    Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

    Description

    A flaw was found in OpenSSH. A malicious SSH server can exploit a double free vulnerability in the Diffie-Hellman Group Exchange (DH-GEX) client path. This occurs during FIPS (Federal Information Processing Standards) mode known-group validation when the client processes attacker-controlled DH-GEX group parameters. Successful exploitation leads to client-side process termination, resulting in a Denial of Service (DoS).

    Source: BSI WID Portal, BSI CSAF, redhat_csaf, cvelistv5, NVD (NIST), Microsoft Security Update Guide, CVE.org (MITRE)

    Affected products

    The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

    Affected products
    Affected versionsFixed in
    Red HatRed Hat Enterprise Linux 10
    • < 0:9.9p1-25.el10_2
    • 0:9.9p1-25.el10_2
    Red HatRed Hat Enterprise Linux 10.0 Extended Update Support
    • < 0:9.9p1-7.el10_0.5
    • 0:9.9p1-7.el10_0.5
    Red HatRed Hat Enterprise Linux 6
    • —
    • —
    Red HatRed Hat Enterprise Linux 7
    • —
    • —
    Red HatRed Hat Enterprise Linux 8
    • < 0:8.0p1-30.el8_10
    • 0:8.0p1-30.el8_10
    Red HatRed Hat Enterprise Linux 9
    • < 0:9.9p1-9.el9_8
    • 0:9.9p1-9.el9_8
    Red HatRed Hat Enterprise Linux 9.2 Update Services for SAP Solutions
    • < 0:8.7p1-30.el9_2.13
    • 0:8.7p1-30.el9_2.13
    Red HatRed Hat Enterprise Linux 9.4 Update Services for SAP Solutions
    • < 0:8.7p1-38.el9_4.10
    • 0:8.7p1-38.el9_4.10
    Red HatRed Hat Enterprise Linux 9.6 Extended Update Support
    • < 0:8.7p1-45.el9_6.5
    • 0:8.7p1-45.el9_6.5
    Red HatRed Hat Hardened Images
    • < 10.3p1-6.hum1
    • 10.3p1-6.hum1
    Red HatRed Hat OpenShift AI 3.0
    • < 1791818496
    • < 1791818502
    • < 1793042072
    • < 1791818589
    • < 1791818590
    • < 1791818505
    • 1791818496
    • 1791818502
    • 1793042072
    • 1791818589
    • 1791818590
    • 1791818505
    Red HatRed Hat OpenShift AI 3.2
    • < 1791818598
    • < 1791818587
    • < 1791818778
    • < 1791818512
    • < 1791818602
    • 1791818598
    • 1791818587
    • 1791818778
    • 1791818512
    • 1791818602
    Red HatRed Hat OpenShift AI 3.3
    • < 1791818877
    • < 1791818627
    • < 1791818874
    • < 1791818792
    • < 1791818790
    • < 1791818662
    • < 1791818782
    • 1791818877
    • 1791818627
    • 1791818874
    • 1791818792
    • 1791818790
    • 1791818662
    • 1791818782
    Red HatRed Hat OpenShift AI 3.4
    • < 1791883722
    • < 1791885618
    • < 1791881612
    • < 1791881487
    • < 1791885505
    • < 1791881769
    • < 1791881486
    • < 1791883315
    • < 1791881732
    • 1791883722
    • 1791885618
    • 1791881612
    • 1791881487
    • 1791885505
    • 1791881769
    • 1791881486
    • 1791883315
    • 1791881732
    Red HatRed Hat OpenShift AI 3.5
    • < 1791818749
    • < 1791818901
    • < 1791819123
    • < 1791820333
    • < 1791819206
    • < 1791819104
    • < 1791819252
    • < 1791818979
    • < 1791819495
    • 1791818749
    • 1791818901
    • 1791819123
    • 1791820333
    • 1791819206
    • 1791819104
    • 1791819252
    • 1791818979
    • 1791819495
    Red HatRed Hat OpenShift Container Platform 4
    • —
    • —
    Red HatRed Hat OpenShift Container Platform 5
    • —
    • —

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxredhatenterprise_linux10.0
    Linuxredhatenterprise_linux6.0
    Linuxredhatenterprise_linux7.0
    Linuxredhatenterprise_linux8.0
    Linuxredhatenterprise_linux9.0

    Weakness classes (CWE)

    Public exploit references

    Publicly reported proof-of-concepts, exploit modules and detection templates for this vulnerability. NEOSEC links to the original sources only and does not provide any exploit code.

    Public exploit references
    Reference tagged as exploitbugzilla.redhat.com (opens in a new tab)PoC (publicly reported)reported, not verified—

    References & sources

    Changes to this CVE

    Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

    1. Record modifiedRed Hat

      1 individual change: Affected versions (publisher)

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/55xxx/CVE-2026-55653.json">CVE-2026-55653</a>

      Source identifier: secalert@redhat.com

    2. Record modifiedRed Hat

      Show 2 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/55xxx/CVE-2026-55653.json">CVE-2026-55653</a>
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:91232

      Source identifier: secalert@redhat.com

    3. Record modifiedRed Hat

      Show 2 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/55xxx/CVE-2026-55653.json">CVE-2026-55653</a>
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:89739

      Source identifier: secalert@redhat.com

    4. Record modifiedRed Hat

      Show 37 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/55xxx/CVE-2026-55653.json">CVE-2026-55653</a>
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82750
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82751
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82752
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82753
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82754
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82755
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82756
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82757
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82758
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82759
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82761
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82762
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82763
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82897
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82898
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82899
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82900
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82901
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82902
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82903
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82904
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82907
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82908
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82909
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82910
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82912
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82913
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82914
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82915
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82916
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82917
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82918
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82920
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82921
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82922
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82923

      Source identifier: secalert@redhat.com

    5. Record modifiedRed Hat

      Show 2 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/55xxx/CVE-2026-55653.json">CVE-2026-55653</a>
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:82749

      Source identifier: secalert@redhat.com

    Show 11 older changes

    1. Record modifiedRed Hat

      Show 2 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/55xxx/CVE-2026-55653.json">CVE-2026-55653</a>
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:80513

      Source identifier: secalert@redhat.com

    2. Record modifiedRed Hat

      Show 2 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/55xxx/CVE-2026-55653.json">CVE-2026-55653</a>
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:76993

      Source identifier: secalert@redhat.com

    3. Record modifiedRed Hat

      Show 2 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/55xxx/CVE-2026-55653.json">CVE-2026-55653</a>
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:76748

      Source identifier: secalert@redhat.com

    4. Record modifiedRed Hat

      1 individual change: Affected versions (publisher)

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/55xxx/CVE-2026-55653.json">CVE-2026-55653</a>

      Source identifier: secalert@redhat.com

    5. Record modifiedRed Hat

      Show 19 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/55xxx/CVE-2026-55653.json">CVE-2026-55653</a>
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:36759
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:47755
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:47756
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:47757
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:54387
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:58981
      Referenceadded
      —
      https://access.redhat.com/security/cve/CVE-2026-55653
      Referenceadded
      —
      https://bugzilla.redhat.com/show_bug.cgi?id=2462351
      Referenceremoved
      https://access.redhat.com/errata/RHSA-2026:36759
      —
      Referenceremoved
      https://access.redhat.com/errata/RHSA-2026:47755
      —
      Referenceremoved
      https://access.redhat.com/errata/RHSA-2026:47756
      —
      Referenceremoved
      https://access.redhat.com/errata/RHSA-2026:47757
      —
      Referenceremoved
      https://access.redhat.com/errata/RHSA-2026:54387
      —
      Referenceremoved
      https://access.redhat.com/errata/RHSA-2026:58981
      —
      Referenceremoved
      https://access.redhat.com/security/cve/CVE-2026-55653
      —
      Referenceremoved
      https://bugzilla.redhat.com/show_bug.cgi?id=2462351
      —
      Reference typeremoved
      https://access.redhat.com/security/cve/CVE-2026-55653 Types: Vendor Advisory
      —
      Reference typeremoved
      https://bugzilla.redhat.com/show_bug.cgi?id=2462351 Types: Exploit, Issue Tracking, Vendor Advisory
      —

      Source identifier: secalert@redhat.com

    6. Record modifiedRed Hat

      1 individual change: Affected versions (publisher)

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)changed
      Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 8 (+9)
      Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 8 (+8)

      Source identifier: secalert@redhat.com

    7. Record modifiedRed Hat

      1 individual change: Affected versions (publisher)

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)changed
      Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 8 (+8)
      Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 8 (+9)

      Source identifier: secalert@redhat.com

    8. Record modifiedRed Hat

      Show 3 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:47756
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:47757
      Affected versions (publisher)changed
      Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 8, Red Hat Hardened Images (+5)
      Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 8 (+6)

      Source identifier: secalert@redhat.com

    9. Record modifiedRed Hat

      Show 2 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:47755
      Affected versions (publisher)changed
      Red Hat Hardened Images, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6 (+4)
      Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 8, Red Hat Hardened Images (+5)

      Source identifier: secalert@redhat.com

    10. Initial analysis by NVDNVD

      Newly listed as affected:

      CVSS V3.1: AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

      Show 4 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      CVSSadded
      —
      AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
      Product configurationadded
      —
      OR *cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:* *cpe:2.3:o:redhat:enterprise_linux:6.0:*:*:*:*:*:*:* *cpe:2.3:a:openbsd:openssh:-:*:*:*:*:*:*:* *cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:* *cpe:2.3:a:redhat:openshift_container_platform:4.0:*:*:*:*:*:*:* *cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:* *cpe:2.3:o:redhat:enterprise_linux:10.0:*:*:*:*:*:*:* *cpe:2.3:a:redhat:hardened_images:-:*:*:*:*:*:*:*
      Reference typeadded
      —
      Red Hat, Inc.: https://access.redhat.com/security/cve/CVE-2026-55653 Types: Vendor Advisory
      Reference typeadded
      —
      Red Hat, Inc.: https://bugzilla.redhat.com/show_bug.cgi?id=2462351 Types: Exploit, Issue Tracking, Vendor Advisory

      Source identifier: nvd@nist.gov

    11. ReceivedRed Hat

      CVSS V3.1: AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L

      Weakness type: CWE-415

      Description added or changed

      Show 6 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7 (+4)
      Descriptionadded
      —
      A flaw was found in OpenSSH. A malicious SSH server can exploit a double free vulnerability in the Diffie-Hellman Group Exchange (DH-GEX) client path. This occurs during FIPS (Federal Information Processing Standards) mode known-group validation when the client processes attacker-controlled DH-GEX group parameters. Successful exploitation leads to client-side process termination, resulting in a Denial of Service (DoS).
      CVSSadded
      —
      AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
      Weakness type (CWE)added
      —
      CWE-415
      Referenceadded
      —
      https://access.redhat.com/security/cve/CVE-2026-55653
      Referenceadded
      —
      https://bugzilla.redhat.com/show_bug.cgi?id=2462351

      Source identifier: secalert@redhat.com

    Embed badge

    Show the severity and KEV status of this vulnerability on your site – with a link back here. The image is updated hourly.

    Badge preview for CVE-2026-55653
    <a href="https://intel.neosec.eu/en/cve/CVE-2026-55653"><img src="https://intel.neosec.eu/badge/cve/CVE-2026-55653.svg?lang=en" alt="CVE-2026-55653 – NEOSEC Intel" height="20"></a>