CriticalCVE-2026-46244

    Linux Kernel: security vulnerability (CVE-2026-46244)

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

    What is affected, what to do

    In the Linux kernel, the following vulnerability has been resolved: netfilter: nft_inner: Fix IPv6 inner_thoff desync In nft_inner_parse_l2l3(), when processing inner IPv6 packets, ipv6_find_hdr() correctly computes the transport header offset traversing all extension headers, but the result is immediately overwritten with nhoff + sizeof(_ip6h) (40 bytes), which only accounts for the IPv6 base header. This creates a desync between inner_thoff (wrong — points to extension header start) and l4proto (correct — e.g., IPPROTO_TCP), enabling transport header forgery and potential firewall bypass.

    Update Linux Kernel to version 6.6.142, Linux Kernel to version 6.12.92, Linux Kernel to version 6.18.34.

    Affected
    • Linux Kernel lt 6.2..6.6.142
    • Linux Kernel lt 6.7..6.12.92
    • Linux Kernel lt 6.13..6.18.34
    • Linux Kernel lt 6.19..7.0.11
    Fixed in
    • Linux Kernel 6.6.142
    • Linux Kernel 6.12.92
    • Linux Kernel 6.18.34
    • Linux Kernel 7.0.11
    • Linux Kernel 7.1

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

    Metrics

    9.1

    Priority

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

    Source: Vendor (CNA), CVSS v3

    9.1

    CVSS v3

    Severity Critical on the scale from 0 to 10.

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

    0.4 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 35.9

    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
    74.20 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
    9.1 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
    9.1
    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
    35.9
    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: netfilter: nft_inner: Fix IPv6 inner_thoff desync In nft_inner_parse_l2l3(), when processing inner IPv6 packets, ipv6_find_hdr() correctly computes the transport header offset traversing all extension headers, but the result is immediately overwritten with nhoff + sizeof(_ip6h) (40 bytes), which only accounts for the IPv6 base header. This creates a desync between inner_thoff (wrong — points to extension header start) and l4proto (correct — e.g., IPPROTO_TCP), enabling transport header forgery and potential firewall bypass. This issue affects stable versions from Linux 6.2. For comparison, the normal (non-inner) IPv6 path correctly preserves ipv6_find_hdr()'s result. Removing the incorrect overwrite ensures that ipv6_find_hdr()'s calculated transport header offset is preserved, thereby fixing the desynchronization.

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

    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
    • 6.19 – < 7.0.11
    • 6.13 – < 6.18.34
    • —
    • 6.7 – < 6.12.92
    • 6.2 – < 6.6.142
    • 7.0.11
    • 6.18.34
    • 7.1
    • 6.12.92
    • 6.6.142

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebianlinuxtrixie
    Linuxlinuxlinux_kernel7.1
    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 modifiedCISA ADP

      Weakness type: CWE-682

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Weakness type (CWE)added
      —
      CWE-682

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

    2. Record modifiedLinux

      Show 15 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://git.kernel.org/stable/c/689bbf48c1f45130086ae1c46ab83ea4c753c601
      Referenceadded
      —
      https://git.kernel.org/stable/c/870d59e2cf218e7418491e26bad768cb16654582
      Referenceadded
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      https://git.kernel.org/stable/c/b6a91f68ebfed9c38e0e9150f58a9b85da07181c
      Referenceadded
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      https://git.kernel.org/stable/c/c161ad9157f5a0429b5ff94d9770faf3bf48d273
      Referenceadded
      —
      https://git.kernel.org/stable/c/d0f98a3617f6ae5b1e95cde1e68e7ead4a1279ce
      Referenceremoved
      https://git.kernel.org/stable/c/689bbf48c1f45130086ae1c46ab83ea4c753c601
      —
      Referenceremoved
      https://git.kernel.org/stable/c/870d59e2cf218e7418491e26bad768cb16654582
      —
      Referenceremoved
      https://git.kernel.org/stable/c/b6a91f68ebfed9c38e0e9150f58a9b85da07181c
      —
      Referenceremoved
      https://git.kernel.org/stable/c/c161ad9157f5a0429b5ff94d9770faf3bf48d273
      —
      Referenceremoved
      https://git.kernel.org/stable/c/d0f98a3617f6ae5b1e95cde1e68e7ead4a1279ce
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/689bbf48c1f45130086ae1c46ab83ea4c753c601 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/870d59e2cf218e7418491e26bad768cb16654582 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/b6a91f68ebfed9c38e0e9150f58a9b85da07181c Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/c161ad9157f5a0429b5ff94d9770faf3bf48d273 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/d0f98a3617f6ae5b1e95cde1e68e7ead4a1279ce 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-2026-46244","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"yes"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:21:20.717778Z"}

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

    4. Record modifiedRed Hat ADP

      Show 22 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:33215
      Referenceadded
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      https://access.redhat.com/errata/RHSA-2026:34094
      Referenceadded
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      https://access.redhat.com/errata/RHSA-2026:34443
      Referenceadded
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      https://access.redhat.com/errata/RHSA-2026:34911
      Referenceadded
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      https://access.redhat.com/errata/RHSA-2026:36018
      Referenceadded
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      https://access.redhat.com/errata/RHSA-2026:55618
      Referenceadded
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      https://access.redhat.com/errata/RHSA-2026:55763
      Referenceadded
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      https://access.redhat.com/errata/RHSA-2026:56225
      Referenceadded
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      https://access.redhat.com/security/cve/CVE-2026-46244
      Referenceadded
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      https://bugzilla.redhat.com/show_bug.cgi?id=2484451
      Referenceadded
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      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-46244.json
      Referenceremoved
      https://access.redhat.com/errata/RHSA-2026:33215
      —
      Referenceremoved
      https://access.redhat.com/errata/RHSA-2026:34094
      —
      Referenceremoved
      https://access.redhat.com/errata/RHSA-2026:34443
      —
      Referenceremoved
      https://access.redhat.com/errata/RHSA-2026:34911
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      Referenceremoved
      https://access.redhat.com/errata/RHSA-2026:36018
      —
      Referenceremoved
      https://access.redhat.com/errata/RHSA-2026:55618
      —
      Referenceremoved
      https://access.redhat.com/errata/RHSA-2026:55763
      —
      Referenceremoved
      https://access.redhat.com/errata/RHSA-2026:56225
      —
      Referenceremoved
      https://access.redhat.com/security/cve/CVE-2026-46244
      —
      Referenceremoved
      https://bugzilla.redhat.com/show_bug.cgi?id=2484451
      —
      Referenceremoved
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-46244.json
      —

      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-2026:56225
      Affected versions (publisher)changed
      Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 10.0 Extended Update Support (+10)
      Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 10.0 Extended Update Support (+11)

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

    Show 2 older changes

    1. Record modifiedRed Hat ADP

      Show 3 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:55618
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:55763
      Affected versions (publisher)changed
      Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 10.0 Extended Update Support, Red Hat Enterprise Linux 9 (+8)
      Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 10.0 Extended Update Support (+10)

      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-2026:34911
      Affected versions (publisher)changed
      Red Hat Enterprise Linux AppStream EUS (v. 10.0), Red Hat Enterprise Linux AppStream E4S (v.9.4), Red Hat Enterprise Linux AppStream EUS (v.9.6) (+16)
      Red Hat Enterprise Linux AppStream EUS (v. 10.0), Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux AppStream E4S (v.9.4) (+20)

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

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    Linked advisories

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