HighCVE-2026-3497

    Ubuntu Openssh: Use of Uninitialized Resource (CVE-2026-3497)

    Published Last modified Sources: Siemens ProductCERT, BSI, Red Hat, Debian LTS, CVE.org, Debian, SUSE, Ubuntu

    What is affected, what to do

    Vulnerability in the OpenSSH GSSAPI delta included in various Linux distributions. This vulnerability affects the GSSAPI patches added by various Linux distributions and does not affect the OpenSSH upstream project itself.

    Update Ubuntu Openssh to version 1:10.0p1-5ubuntu5.1, Ubuntu Openssh to version 1:9.6p1-3ubuntu13.15, Ubuntu Openssh to version 1:8.9p1-3ubuntu0.14.

    Affected
    • Ubuntu Openssh lt 1:10.0p1-5ubuntu5..1:10.0p1-5ubuntu5.1
    • Ubuntu Openssh lt 1:9.6p1-3ubuntu13..1:9.6p1-3ubuntu13.15
    • Ubuntu Openssh lt 1:8.9p1-3..1:8.9p1-3ubuntu0.14
    Fixed in
    • Ubuntu Openssh 1:10.0p1-5ubuntu5.1
    • Ubuntu Openssh 1:9.6p1-3ubuntu13.15
    • Ubuntu Openssh 1:8.9p1-3ubuntu0.14

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

    Metrics

    8.2

    Priority

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

    Source: Vendor (CNA), CVSS v3

    7.5

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: Siemens ProductCERT, BSI, Red Hat, Debian LTS, CVE.org, Debian, SUSE, Ubuntu

    2.2 %

    EPSS score

    Moderate — model estimates 1-10% exploitation likelihood.

    Source: FIRST EPSS, percentile 82.6

    Show all metrics
    Severity
    High
    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
    107.19 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
    no public PoC known
    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
    8.2 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
    7.5
    CVSS v4

    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
    2.7
    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
    2.2 %
    Moderate — model estimates 1-10% 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
    82.6
    Critical — this CVE ranks in the top fifth of all CVEs scored today (rank ≥ 80%).
    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
    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-908

    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
    High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.
    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

    Vulnerability in the OpenSSH GSSAPI delta included in various Linux distributions. This vulnerability affects the GSSAPI patches added by various Linux distributions and does not affect the OpenSSH upstream project itself. The usage of sshpkt_disconnect() on an error, which does not terminate the process, allows an attacker to send an unexpected GSSAPI message type during the GSSAPI key exchange to the server, which will call the underlying function and continue the execution of the program without setting the related connection variables. As the variables are not initialized to NULL the code later accesses those uninitialized variables, accessing random memory, which could lead to undefined behavior. The recommended workaround is to use ssh_packet_disconnect() instead, which does terminate the process. The impact of the vulnerability depends heavily on the compiler flag hardening configuration.

    Source: siemens_advisory, BSI WID Portal, BSI CSAF, redhat_csaf, Debian LTS Advisories, cvelistv5, NVD (NIST), Debian Security Advisories, CVE.org (MITRE), suse_csaf, Ubuntu Security Notices

    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
    Ubuntuopenssh
    • 1:9.6p1-3ubuntu13 – < 1:9.6p1-3ubuntu13.15
    • 1:8.9p1-3 – < 1:8.9p1-3ubuntu0.14
    • 1:10.0p1-5ubuntu5 – < 1:10.0p1-5ubuntu5.1
    • 1:9.6p1-3ubuntu13.15
    • 1:8.9p1-3ubuntu0.14
    • 1:10.0p1-5ubuntu5.1
    canonicalubuntu_linux
    • 25.10
    • —
    openbsdopenssh
    • —
    • —
    IBMQRadar SIEM
    • <7.5.0 UP15 IF02
    • —
    Open SourceOpenSSH
    • GSSAPI delta Linux distributions
    • —
    Red HatOpenShift Container Platform
    • < 4.17.54
    • < 4.19.32
    • < 4.15.64
    • 4.17.54
    • 4.19.32
    • 4.15.64
    XeroxFreeFlow Print Server
    • v7
    • v2
    • —
    • —

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebiandebian_linux11.0
    Linuxredhatenterprise_linux10.0
    Linuxredhatenterprise_linux8.0
    Linuxredhatenterprise_linux9.0
    Linuxdebianopensshbookworm
    Linuxdebianopensshbullseye
    Linuxdebianopensshtrixie
    Linuxubuntuopensshjammy
    Linuxubuntuopensshnoble
    Linuxubuntuopensshquesting
    Linuxcanonicalubuntu_linux20.04
    Linuxcanonicalubuntu_linux22.04
    Linuxcanonicalubuntu_linux24.04

    Weakness classes (CWE)

    • CWE-908Use of Uninitialized Resource

      Base

      The product uses or accesses a resource that has not been initialized.

      Entry at MITRE CWE-908

    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 modifiedubuntu.com

      Show 6 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
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      https://ubuntu.com/security/CVE-2026-3497
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      https://www.openwall.com/lists/oss-security/2026/03/12/3
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      https://ubuntu.com/security/CVE-2026-3497
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      https://www.openwall.com/lists/oss-security/2026/03/12/3
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      Reference typeremoved
      https://ubuntu.com/security/CVE-2026-3497 Types: Third Party Advisory
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      https://www.openwall.com/lists/oss-security/2026/03/12/3 Types: Mailing List, Third Party Advisory
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      Source identifier: security@ubuntu.com

    2. Record modifiedCVE Program

      Show 24 original changes
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      http://www.openwall.com/lists/oss-security/2026/03/12/3
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      http://www.openwall.com/lists/oss-security/2026/03/14/3
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      http://www.openwall.com/lists/oss-security/2026/03/14/4
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      http://www.openwall.com/lists/oss-security/2026/03/18/2
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      http://www.openwall.com/lists/oss-security/2026/03/18/7
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      https://lists.debian.org/debian-lts-announce/2026/04/msg00014.html
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      http://www.openwall.com/lists/oss-security/2026/03/12/3
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      http://www.openwall.com/lists/oss-security/2026/03/14/3
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      https://lists.debian.org/debian-lts-announce/2026/04/msg00014.html
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      http://www.openwall.com/lists/oss-security/2026/03/12/3 Types: Mailing List, Third Party Advisory
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      http://www.openwall.com/lists/oss-security/2026/03/14/3 Types: Mailing List, Third Party Advisory
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      http://www.openwall.com/lists/oss-security/2026/03/14/4 Types: Mailing List, Third Party Advisory
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      http://www.openwall.com/lists/oss-security/2026/03/18/2 Types: Mailing List, Third Party Advisory
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      http://www.openwall.com/lists/oss-security/2026/03/18/4 Types: Mailing List, Third Party Advisory
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      http://www.openwall.com/lists/oss-security/2026/03/18/5 Types: Mailing List, Third Party Advisory
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      http://www.openwall.com/lists/oss-security/2026/03/18/7 Types: Mailing List, Third Party Advisory
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      Reference typeremoved
      https://lists.debian.org/debian-lts-announce/2026/04/msg00014.html Types: Mailing List, Third Party Advisory
      —

      Source identifier: af854a3a-2127-422b-91ae-364da2661108

    3. Record modifiedRed Hat ADP

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      https://access.redhat.com/errata/RHSA-2026:10065
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      https://access.redhat.com/errata/RHSA-2026:10714
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      https://access.redhat.com/errata/RHSA-2026:12071
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      https://access.redhat.com/errata/RHSA-2026:13750
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      https://access.redhat.com/errata/RHSA-2026:13812
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      https://access.redhat.com/errata/RHSA-2026:14773
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      https://access.redhat.com/errata/RHSA-2026:14924
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      https://access.redhat.com/errata/RHSA-2026:15087
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      https://access.redhat.com/errata/RHSA-2026:15891
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      https://access.redhat.com/errata/RHSA-2026:16008
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      https://access.redhat.com/errata/RHSA-2026:16009
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      https://access.redhat.com/errata/RHSA-2026:16030
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      https://access.redhat.com/errata/RHSA-2026:16174
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      https://access.redhat.com/errata/RHSA-2026:17596
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      https://access.redhat.com/errata/RHSA-2026:19724
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      https://access.redhat.com/errata/RHSA-2026:20040
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      https://access.redhat.com/errata/RHSA-2026:20087
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      https://access.redhat.com/errata/RHSA-2026:21690
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      https://access.redhat.com/errata/RHSA-2026:21695
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      https://access.redhat.com/errata/RHSA-2026:25096
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      https://access.redhat.com/errata/RHSA-2026:5475
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      https://access.redhat.com/errata/RHSA-2026:7107
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      https://access.redhat.com/errata/RHSA-2026:9415
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      https://access.redhat.com/errata/RHSA-2026:9732
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      https://access.redhat.com/security/cve/CVE-2026-3497
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      https://bugzilla.redhat.com/show_bug.cgi?id=2447085
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      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-3497.json
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      https://access.redhat.com/errata/RHSA-2026:10065
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      https://access.redhat.com/errata/RHSA-2026:10714
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      https://access.redhat.com/errata/RHSA-2026:12071
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      https://access.redhat.com/errata/RHSA-2026:13750
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      https://access.redhat.com/errata/RHSA-2026:13812
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      https://access.redhat.com/errata/RHSA-2026:14773
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      https://access.redhat.com/errata/RHSA-2026:14924
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      https://access.redhat.com/errata/RHSA-2026:17596
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      https://access.redhat.com/errata/RHSA-2026:9732
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      https://bugzilla.redhat.com/show_bug.cgi?id=2447085
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      Source identifier: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

    4. Record modifiedSiemens ADP

      Show 4 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/2026/3xxx/CVE-2026-3497.json">CVE-2026-3497</a>
      Referenceadded
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      https://cert-portal.siemens.com/productcert/html/ssa-019113.html
      Referenceadded
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      https://cert-portal.siemens.com/productcert/html/ssa-457936.html
      Referenceremoved
      https://cert-portal.siemens.com/productcert/html/ssa-019113.html
      —

      Source identifier: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e

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