CriticalCVE-2026-52993

    Linux Kernel: Release of Invalid Pointer or Reference (CVE-2026-52993)

    Published Last modified Sources: Ubuntu, Debian LTS, BSI, SUSE, Red Hat, OSV, CVE.org, Msrc Update Guide

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    What is affected, what to do

    A flaw was found in the Linux kernel's Transparent Inter-Process Communication (TIPC) module. This vulnerability, a double-free, occurs when the `tipc_buf_append()` function incorrectly handles memory after a socket buffer (skb) reallocation.

    Update Linux Kernel to version 5.10.258, Linux Kernel to version 5.15.209, Linux Kernel to version 6.1.175.

    Affected
    • Linux Kernel lt 4.15..5.10.258
    • Linux Kernel lt 5.11..5.15.209
    • Linux Kernel lt 5.16..6.1.175
    • Linux Kernel lt 6.2..6.6.141
    • Linux Kernel lt 6.7..6.12.91
    • Linux Kernel lt 6.13..6.18.33
    • Linux Kernel lt 6.19..7.0.10
    Fixed in
    • Linux Kernel 5.10.258
    • Linux Kernel 5.15.209
    • Linux Kernel 6.1.175
    • Linux Kernel 6.6.141
    • Linux Kernel 6.12.91
    • Linux Kernel 6.18.33
    • Linux Kernel 7.0.10
    • Linux Kernel 7.1

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

    Metrics

    9.8

    Priority

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

    Source: NVD, CVSS v3

    9.8

    CVSS v3

    Severity Critical on the scale from 0 to 10.

    Source: Ubuntu, Debian LTS, BSI, SUSE, Red Hat, OSV, CVE.org, Msrc Update Guide

    0.4 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 34.8

    Show all metrics
    Severity
    Critical
    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
    77.71 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
    9.8 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
    9.8
    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
    0.4 %
    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
    34.8
    Elevated — this CVE ranks above at least 10% of all CVEs scored today.
    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 · automatable · Technical impact: total
    Source: CISA Vulnrichment, as of 16 October 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-763

    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

    A flaw was found in the Linux kernel's Transparent Inter-Process Communication (TIPC) module. This vulnerability, a double-free, occurs when the `tipc_buf_append()` function incorrectly handles memory after a socket buffer (skb) reallocation. An attacker could potentially exploit this to cause system instability or a denial of service. In some scenarios, this type of memory corruption could also lead to arbitrary code execution.

    Source: Ubuntu Security Notices, Debian LTS Advisories, BSI WID Portal, BSI CSAF, suse_csaf, redhat_csaf, OSV (Open Source Vulnerabilities), NVD (NIST), CVE.org (MITRE), cvelistv5, Microsoft Security Update Guide

    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
    LinuxLinux
    • 5.16 – < 6.1.175
    • 4.15 – < 5.10.258
    • 5.11 – < 5.15.209
    • 6.7 – < 6.12.91
    • —
    • 6.13 – < 6.18.33
    • 6.2 – < 6.6.141
    • 6.19 – < 7.0.10
    • 6.1.175
    • 5.10.258
    • 5.15.209
    • 6.12.91
    • 7.1
    • 6.18.33
    • 6.6.141
    • 7.0.10
    GoogleAndroid
    • < 2026-09-05
    • < 2026-09-01
    • 2026-09-05
    • 2026-09-01
    IBMQRadar SIEM
    • <7.5.0 UP15 IF06
    • —
    android:linux_kernel:
    • Kernel
    • :0
    • —
    • :2026-09-05

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxubuntuawsbionic
    Linuxubuntuawsjammy
    Linuxubuntuawsnoble
    Linuxubuntuawsresolute
    Linuxubuntuawsxenial
    Linuxubuntuaws-6.8jammy
    Linuxubuntuaws-hwexenial
    Linuxubuntuazurejammy
    Linuxubuntuazurenoble
    Linuxubuntuazureresolute
    Linuxubuntuazurexenial
    Linuxubuntuazure-4.15bionic
    Linuxubuntugcpjammy
    Linuxubuntugcpnoble
    Linuxubuntugcpresolute
    Linuxubuntugcpxenial
    Linuxubuntugcp-4.15bionic
    Linuxubuntugcp-6.8jammy
    Linuxubuntugeneric-4.15bionic
    Linuxubuntugeneric-4.15xenial
    Linuxubuntugeneric-4.4xenial
    Linuxubuntugeneric-5.4bionic
    Linuxubuntugeneric-5.4focal
    Linuxubuntugkejammy

    Weakness classes (CWE)

    • CWE-763Release of Invalid Pointer or Reference

      Base

      The product attempts to return a memory resource to the system, but it calls the wrong release function or calls the appropriate release function incorrectly.

      Entry at MITRE CWE-763

    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 modifiedCISA ADP

      Weakness type: CWE-763

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Weakness type (CWE)added
      —
      CWE-763

      Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

    2. Record modifiedLinux

      Show 24 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://git.kernel.org/stable/c/0274f24485fc38032d4093e463dc3ff5c7a667c9
      Referenceadded
      —
      https://git.kernel.org/stable/c/1d5e589055880fae229e229e1929e087dbe08cf3
      Referenceadded
      —
      https://git.kernel.org/stable/c/29940fff14110ca48c5ccc168d121665b51bb778
      Referenceadded
      —
      https://git.kernel.org/stable/c/4d104882bc815d4ec666ace9155f5f52715879a6
      Referenceadded
      —
      https://git.kernel.org/stable/c/4ee4deadaae7cb2e3d53af0fc889cf92a73413c0
      Referenceadded
      —
      https://git.kernel.org/stable/c/a438975a6dcdbd70865978c021650d1485586f0b
      Referenceadded
      —
      https://git.kernel.org/stable/c/d293ca716e7d5dffdaecaf6b9b2f857a33dc3d3a
      Referenceadded
      —
      https://git.kernel.org/stable/c/d3556656c6daebf8def751c7e71d11dd0a180d24
      Referenceremoved
      https://git.kernel.org/stable/c/0274f24485fc38032d4093e463dc3ff5c7a667c9
      —
      Referenceremoved
      https://git.kernel.org/stable/c/1d5e589055880fae229e229e1929e087dbe08cf3
      —
      Referenceremoved
      https://git.kernel.org/stable/c/29940fff14110ca48c5ccc168d121665b51bb778
      —
      Referenceremoved
      https://git.kernel.org/stable/c/4d104882bc815d4ec666ace9155f5f52715879a6
      —
      Referenceremoved
      https://git.kernel.org/stable/c/4ee4deadaae7cb2e3d53af0fc889cf92a73413c0
      —
      Referenceremoved
      https://git.kernel.org/stable/c/a438975a6dcdbd70865978c021650d1485586f0b
      —
      Referenceremoved
      https://git.kernel.org/stable/c/d293ca716e7d5dffdaecaf6b9b2f857a33dc3d3a
      —
      Referenceremoved
      https://git.kernel.org/stable/c/d3556656c6daebf8def751c7e71d11dd0a180d24
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/0274f24485fc38032d4093e463dc3ff5c7a667c9 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/1d5e589055880fae229e229e1929e087dbe08cf3 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/29940fff14110ca48c5ccc168d121665b51bb778 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/4d104882bc815d4ec666ace9155f5f52715879a6 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/4ee4deadaae7cb2e3d53af0fc889cf92a73413c0 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/a438975a6dcdbd70865978c021650d1485586f0b Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/d293ca716e7d5dffdaecaf6b9b2f857a33dc3d3a Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/d3556656c6daebf8def751c7e71d11dd0a180d24 Types: Patch
      —

      Source identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    3. Record modifiedCISA ADP

      CISA assessment (SSVC): exploitation: none known, automatable: yes

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      SSVC assessmentadded
      —
      {"id":"CVE-2026-52993","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"yes"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:24:18.442775Z"}

      Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

    4. Record modifiedRed Hat ADP

      Show 17 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:45115
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:45116
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:47017
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:49212
      Referenceadded
      —
      https://access.redhat.com/security/cve/CVE-2026-52993
      Referenceadded
      —
      https://bugzilla.redhat.com/show_bug.cgi?id=2492437
      Referenceadded
      —
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52993.json
      Referenceremoved
      https://access.redhat.com/errata/RHSA-2026:45115
      —
      Referenceremoved
      https://access.redhat.com/errata/RHSA-2026:45116
      —
      Referenceremoved
      https://access.redhat.com/errata/RHSA-2026:47017
      —
      Referenceremoved
      https://access.redhat.com/errata/RHSA-2026:49212
      —
      Referenceremoved
      https://access.redhat.com/security/cve/CVE-2026-52993
      —
      Referenceremoved
      https://bugzilla.redhat.com/show_bug.cgi?id=2492437
      —
      Referenceremoved
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52993.json
      —
      Reference typeremoved
      https://access.redhat.com/security/cve/CVE-2026-52993 Types: Third Party Advisory
      —
      Reference typeremoved
      https://bugzilla.redhat.com/show_bug.cgi?id=2492437 Types: Third Party Advisory
      —
      Reference typeremoved
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52993.json Types: Third Party Advisory
      —

      Source identifier: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

    5. Record modifiedRed Hat ADP

      Show 2 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:49212
      Affected versions (publisher)changed
      Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 8 (+5)
      Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 8 (+5)

      Source identifier: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

    Show 4 older changes

    1. Record modifiedRed Hat ADP

      Show 2 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:47017
      Affected versions (publisher)changed
      Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 10 (+5)
      Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 8 (+5)

      Source identifier: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

    2. Record modifiedRed Hat ADP

      Show 2 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:45116
      Affected versions (publisher)changed
      Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6 (+5)
      Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 10 (+5)

      Source identifier: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

    3. Record modifiedRed Hat ADP

      Show 2 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:45115
      Affected versions (publisher)changed
      Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7 (+5)
      Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6 (+5)

      Source identifier: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

    4. ReceivedLinux

      Description added or changed

      Show 10 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      Linux, Linux
      Descriptionadded
      —
      In the Linux kernel, the following vulnerability has been resolved: tipc: fix double-free in tipc_buf_append() tipc_msg_validate() can potentially reallocate the skb it is validating, freeing the old one. In tipc_buf_append(), it was being called with a pointer to a local variable which was a copy of the caller's skb pointer. If the skb was reallocated and validation subsequently failed, the error handling path would free the original skb pointer, which had already been freed, leading to double-free. Fix this by checking if head now points to a newly allocated reassembled skb. If it does, reassign *headbuf for later freeing operations.
      Referenceadded
      —
      https://git.kernel.org/stable/c/0274f24485fc38032d4093e463dc3ff5c7a667c9
      Referenceadded
      —
      https://git.kernel.org/stable/c/1d5e589055880fae229e229e1929e087dbe08cf3
      Referenceadded
      —
      https://git.kernel.org/stable/c/29940fff14110ca48c5ccc168d121665b51bb778
      Referenceadded
      —
      https://git.kernel.org/stable/c/4d104882bc815d4ec666ace9155f5f52715879a6
      Referenceadded
      —
      https://git.kernel.org/stable/c/4ee4deadaae7cb2e3d53af0fc889cf92a73413c0
      Referenceadded
      —
      https://git.kernel.org/stable/c/a438975a6dcdbd70865978c021650d1485586f0b
      Referenceadded
      —
      https://git.kernel.org/stable/c/d293ca716e7d5dffdaecaf6b9b2f857a33dc3d3a
      Referenceadded
      —
      https://git.kernel.org/stable/c/d3556656c6daebf8def751c7e71d11dd0a180d24

      Source identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

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