HighCVE-2026-31629

    Linux Kernel: Use-After-Free (CVE-2026-31629)

    Published Last modified Sources: SUSE, Debian, Debian LTS, Ubuntu, Siemens ProductCERT, BSI, Msrc Update Guide, CVE.org, OSV, EUVD

    What is affected, what to do

    In the Linux kernel, the following vulnerability has been resolved: nfc: llcp: add missing return after LLCP_CLOSED checks In nfc_llcp_recv_hdlc() and nfc_llcp_recv_disc(), when the socket state is LLCP_CLOSED, the code correctly calls release_sock() and nfc_llcp_sock_put() but fails to return. Execution falls through to the remainder of the function, which calls release_sock() and nfc_llcp_sock_put() again.

    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 3.3..5.10.258
    • Linux Kernel lt 5.11..5.15.209
    • Linux Kernel lt 5.16..6.1.175
    • Linux Kernel lt 6.2..6.6.136
    • Linux Kernel lt 6.7..6.12.83
    • Linux Kernel lt 6.13..6.18.24
    • Linux Kernel lt 6.19..6.19.14
    • Linux Kernel lt 6.20..7.0.1
    Fixed in
    • Linux Kernel 5.10.258
    • Linux Kernel 5.15.209
    • Linux Kernel 6.1.175
    • Linux Kernel 6.6.136
    • Linux Kernel 6.12.83
    • Linux Kernel 6.18.24
    • Linux Kernel 6.19.14
    • Linux Kernel 7.0.1
    • Linux Kernel 7.1

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

    Metrics

    8.8

    Priority

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

    Source: NVD, CVSS v3

    8.8

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: SUSE, Debian, Debian LTS, Ubuntu, Siemens ProductCERT, BSI, Msrc Update Guide, CVE.org, OSV, EUVD

    0.3 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 16.7

    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
    62.83 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
    8.8 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
    8.8
    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
    0.3 %
    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
    16.7
    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

    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

    In the Linux kernel, the following vulnerability has been resolved: nfc: llcp: add missing return after LLCP_CLOSED checks In nfc_llcp_recv_hdlc() and nfc_llcp_recv_disc(), when the socket state is LLCP_CLOSED, the code correctly calls release_sock() and nfc_llcp_sock_put() but fails to return. Execution falls through to the remainder of the function, which calls release_sock() and nfc_llcp_sock_put() again. This results in a double release_sock() and a refcount underflow via double nfc_llcp_sock_put(), leading to a use-after-free. Add the missing return statements after the LLCP_CLOSED branches in both functions to prevent the fall-through.

    Source: suse_csaf, Debian Security Advisories, Debian LTS Advisories, Ubuntu Security Notices, siemens_advisory, BSI WID Portal, BSI CSAF, Microsoft Security Update Guide, cvelistv5, OSV (Open Source Vulnerabilities), NVD (NIST), ENISA EUVD, 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
    LinuxLinux
    • 5.16 – < 6.1.175
    • 6.2 – < 6.6.136
    • 6.19 – < 6.19.14
    • 5.11 – < 5.15.209
    • 6.13 – < 6.18.24
    • —
    • 6.7 – < 6.12.83
    • 6.20 – < 7.0.1
    • 3.3 – < 5.10.258
    • 6.1.175
    • 6.6.136
    • 6.19.14
    • 5.15.209
    • 6.18.24
    • 7.1
    • 6.12.83
    • 7.0.1
    • 5.10.258
    GoogleAndroid
    • < 2026-09-05
    • < 2026-09-01
    • 2026-09-05
    • 2026-09-01
    SiemensSIMATIC S7
    • 1500 TM MFP V1.1.1 GNU/Linux subsystem
    • —
    android:linux_kernel:
    • Kernel
    • :0
    • —
    • :2026-09-05

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebianlinuxbookworm
    Linuxdebianlinuxbullseye
    Linuxdebianlinuxtrixie
    Linuxdebianlinux-6.1bullseye
    Linuxlinuxlinux_kernel—

    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 modifiedLinux

      Show 24 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://git.kernel.org/stable/c/0eb1263a3b8c36418c9ba295c9ab3abed664edbf
      Referenceadded
      —
      https://git.kernel.org/stable/c/2b5dd4632966c39da6ba74dbc8689b309065e82c
      Referenceadded
      —
      https://git.kernel.org/stable/c/665315df9c3486cb213fc44d83cc8bcd47fe0d26
      Referenceadded
      —
      https://git.kernel.org/stable/c/796e0cac058252d0ad34ebe288e6f7979b5fc9b2
      Referenceadded
      —
      https://git.kernel.org/stable/c/8977fad2b3c6eefd414131168d597c5d1d5e1abf
      Referenceadded
      —
      https://git.kernel.org/stable/c/9b49e2a4b8219a2fc5cebf94f4ec34e509aff8a6
      Referenceadded
      —
      https://git.kernel.org/stable/c/aba4712e8f0381cd5d196534ce2ad082626a5ab6
      Referenceadded
      —
      https://git.kernel.org/stable/c/b2a23529593d011fb433a3d711fc597ed6a6bd2f
      Referenceadded
      —
      https://git.kernel.org/stable/c/ff3d9e8f7244293e303f7b6ef70774291c7c27e9
      Referenceremoved
      https://git.kernel.org/stable/c/0eb1263a3b8c36418c9ba295c9ab3abed664edbf
      —
      Referenceremoved
      https://git.kernel.org/stable/c/2b5dd4632966c39da6ba74dbc8689b309065e82c
      —
      Referenceremoved
      https://git.kernel.org/stable/c/665315df9c3486cb213fc44d83cc8bcd47fe0d26
      —
      Referenceremoved
      https://git.kernel.org/stable/c/796e0cac058252d0ad34ebe288e6f7979b5fc9b2
      —
      Referenceremoved
      https://git.kernel.org/stable/c/8977fad2b3c6eefd414131168d597c5d1d5e1abf
      —
      Referenceremoved
      https://git.kernel.org/stable/c/9b49e2a4b8219a2fc5cebf94f4ec34e509aff8a6
      —
      Referenceremoved
      https://git.kernel.org/stable/c/aba4712e8f0381cd5d196534ce2ad082626a5ab6
      —
      Referenceremoved
      https://git.kernel.org/stable/c/b2a23529593d011fb433a3d711fc597ed6a6bd2f
      —
      Referenceremoved
      https://git.kernel.org/stable/c/ff3d9e8f7244293e303f7b6ef70774291c7c27e9
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/0eb1263a3b8c36418c9ba295c9ab3abed664edbf Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/2b5dd4632966c39da6ba74dbc8689b309065e82c Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/796e0cac058252d0ad34ebe288e6f7979b5fc9b2 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/8977fad2b3c6eefd414131168d597c5d1d5e1abf Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/aba4712e8f0381cd5d196534ce2ad082626a5ab6 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/ff3d9e8f7244293e303f7b6ef70774291c7c27e9 Types: Patch
      —

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

    2. Record modifiedSiemens ADP

      Show 2 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/31xxx/CVE-2026-31629.json">CVE-2026-31629</a>
      Referenceadded
      —
      https://cert-portal.siemens.com/productcert/html/ssa-784472.html

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

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