LowCVE-2026-80843

    Linux Kernel: security vulnerability (CVE-2026-80843)

    Published Last modified Sources: Ubuntu, HKCERT, Debian LTS, Debian, BSI, CVE.org, EUVD, Msrc Update Guide

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    What is affected, what to do

    In the Linux kernel, the following vulnerability has been resolved: xfrm: fix xfrm_state_construct() auth-trunc leak attach_auth_trunc() can allocate x->aalg while leaving x->props.aalgo at zero when the selected auth algorithm has no sadb_alg_id. One real case is cmac(aes). xfrm_state_construct() then treats !x->props.aalgo as "no auth algorithm attached yet" and calls attach_auth().

    Update Linux Kernel to version 5.10.269, Linux Kernel to version 5.15.220, Linux Kernel to version 6.1.187.

    Affected
    • Linux Kernel lt 2.6.33..5.10.269
    • Linux Kernel lt 5.11..5.15.220
    • Linux Kernel lt 5.16..6.1.187
    • Linux Kernel lt 6.2..6.6.156
    • Linux Kernel lt 6.7..6.12.108
    • Linux Kernel lt 6.13..6.18.49
    • Linux Kernel lt 6.19..7.1.13
    • Linux Kernel lt 7.2..7.2.3
    Fixed in
    • Linux Kernel 5.10.269
    • Linux Kernel 5.15.220
    • Linux Kernel 6.1.187
    • Linux Kernel 6.6.156
    • Linux Kernel 6.12.108
    • Linux Kernel 6.18.49
    • Linux Kernel 7.1.13
    • Linux Kernel 7.2.3
    • Linux Kernel 7.3

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

    Metrics

    2.3

    XIEM Effective CVSS

    Highest available CVSS rating from NVD and vendor data.

    Source: Vendor (CNA), CVSS v3

    2.3

    CVSS v3

    Severity Low on the scale from 0 to 10.

    Source: Ubuntu, HKCERT, Debian LTS, Debian, BSI, CVE.org, EUVD, Msrc Update Guide

    0.2 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 9.3

    Show all metrics
    Severity
    Low
    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
    36.26 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
    2.3 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
    2.3
    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
    0.2 %
    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
    9.3
    Low — this CVE sits in the lower 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
    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

    In the Linux kernel, the following vulnerability has been resolved: xfrm: fix xfrm_state_construct() auth-trunc leak attach_auth_trunc() can allocate x->aalg while leaving x->props.aalgo at zero when the selected auth algorithm has no sadb_alg_id. One real case is cmac(aes). xfrm_state_construct() then treats !x->props.aalgo as "no auth algorithm attached yet" and calls attach_auth(). That overwrites x->aalg and loses the first allocation. Any later failure or teardown only frees the replacement pointer. Check whether x->aalg is already attached instead of inferring that state from x->props.aalgo.

    Source: Ubuntu Security Notices, HKCERT (CC BY 3.0 HK) · HKCERT rating: medium, Debian LTS Advisories, Debian Security Advisories, BSI WID Portal, BSI CSAF, cvelistv5, ENISA EUVD, NVD (NIST), CVE.org (MITRE), 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
    • 6.13 – < 6.18.49
    • 5.11 – < 5.15.220
    • 5.16 – < 6.1.187
    • 6.7 – < 6.12.108
    • 7.2 – < 7.2.3
    • —
    • 6.19 – < 7.1.13
    • 6.2 – < 6.6.156
    • 2.6.33 – < 5.10.269
    • 6.18.49
    • 5.15.220
    • 6.1.187
    • 6.12.108
    • 7.2.3
    • 7.3
    • 7.1.13
    • 6.6.156
    • 5.10.269
    Red HatOpenShift
    • Container Platform
    • —

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebianlinuxbookworm
    Linuxdebianlinuxtrixie
    Linuxubuntulinuxjammy
    Linuxubuntulinuxnoble
    Linuxubuntulinuxresolute
    Linuxdebianlinux-6.12bookworm
    Linuxubuntulinux-awsjammy
    Linuxubuntulinux-awsnoble
    Linuxubuntulinux-awsresolute
    Linuxubuntulinux-aws-5.15focal
    Linuxubuntulinux-aws-6.8jammy
    Linuxubuntulinux-aws-7.0noble
    Linuxubuntulinux-aws-fipsjammy
    Linuxubuntulinux-aws-fipsnoble
    Linuxubuntulinux-azurejammy
    Linuxubuntulinux-azurenoble
    Linuxubuntulinux-azureresolute
    Linuxubuntulinux-azure-5.15focal
    Linuxubuntulinux-azure-6.8jammy
    Linuxubuntulinux-azure-fdejammy
    Linuxubuntulinux-azure-fdenoble
    Linuxubuntulinux-azure-fderesolute
    Linuxubuntulinux-azure-fde-5.15focal
    Linuxubuntulinux-azure-fde-6.8jammy

    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

      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/2026/80xxx/CVE-2026-80843.json">CVE-2026-80843</a>

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

    2. ReceivedLinux

      Description added or changed

      Show 11 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Descriptionadded
      —
      In the Linux kernel, the following vulnerability has been resolved: xfrm: fix xfrm_state_construct() auth-trunc leak attach_auth_trunc() can allocate x->aalg while leaving x->props.aalgo at zero when the selected auth algorithm has no sadb_alg_id. One real case is cmac(aes). xfrm_state_construct() then treats !x->props.aalgo as "no auth algorithm attached yet" and calls attach_auth(). That overwrites x->aalg and loses the first allocation. Any later failure or teardown only frees the replacement pointer. Check whether x->aalg is already attached instead of inferring that state from x->props.aalgo.
      Affected versions (publisher)added
      —
      New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/80xxx/CVE-2026-80843.json">CVE-2026-80843</a>
      Referenceadded
      —
      https://git.kernel.org/stable/c/37426395cb90ef217beec8407a14bd82153793d3
      Referenceadded
      —
      https://git.kernel.org/stable/c/71d42da01740ec6557837bebec0bc48cfc3b4c39
      Referenceadded
      —
      https://git.kernel.org/stable/c/958ae9f261319e1cdc44879886bcda2263258cca
      Referenceadded
      —
      https://git.kernel.org/stable/c/ba0c110c205855b3f1e3130d8c0fdb484d704c8c
      Referenceadded
      —
      https://git.kernel.org/stable/c/be19d20e53a239572bb2a28efcc1cd2b069b1ef9
      Referenceadded
      —
      https://git.kernel.org/stable/c/c12cbf56320fb633484ee0ca1fb7d68d6b64b213
      Referenceadded
      —
      https://git.kernel.org/stable/c/c8837bbe792257af547fd1c0252553ce13148795
      Referenceadded
      —
      https://git.kernel.org/stable/c/cf67361e78dca488d6e4df8396a53e6745a3a80e
      Referenceadded
      —
      https://git.kernel.org/stable/c/fb7f3e74789a3c89647f4eb768f6dfaf4a751e72

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

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