HighCVE-2026-63968

    Linux Kernel: Infinite Loop (CVE-2026-63968)

    Published Last modified Sources: SUSE, Ubuntu, HKCERT, CVE.org, BSI

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    What is affected, what to do

    In the Linux kernel, the following vulnerability has been resolved: ipv6: fix possible infinite loop in fib6_select_path() Found while auditing the same pattern Sashiko reported in rt6_fill_node() [1]. Apply the same fix as commit f8d8ce1b515a ("ipv6: fix possible infinite loop in fib6_info_uses_dev()").

    Update Linux Kernel to version 6.1.176, Linux Kernel to version 6.6.143, Linux Kernel to version 6.12.93.

    Affected
    • Linux Kernel lt 6.1.128..6.1.176
    • Linux Kernel lt 6.6.75..6.6.143
    • Linux Kernel lt 6.12.2..6.12.93
    • Linux Kernel lt 6.11.11..6.12
    • Linux Kernel lt 6.13..6.18.35
    • Linux Kernel lt 6.19..7.0.12
    Fixed in
    • Linux Kernel 6.1.176
    • Linux Kernel 6.6.143
    • Linux Kernel 6.12.93
    • Linux Kernel 6.12
    • Linux Kernel 6.18.35
    • Linux Kernel 7.0.12
    • Linux Kernel 7.1

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

    Metrics

    7.5

    Priority

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

    Source: NVD, CVSS v3

    7.5

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: SUSE, Ubuntu, HKCERT, CVE.org, BSI

    0.7 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 51.8

    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
    79.69 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
    7.5 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
    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
    0.7 %
    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
    51.8
    High — this CVE ranks above the median of all CVEs scored today (rank ≥ 36%).
    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: partial
    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-835, CWE-835

    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: ipv6: fix possible infinite loop in fib6_select_path() Found while auditing the same pattern Sashiko reported in rt6_fill_node() [1]. Apply the same fix as commit f8d8ce1b515a ("ipv6: fix possible infinite loop in fib6_info_uses_dev()"). Writers holding tb6_lock can list_del_rcu(&first->fib6_siblings) without waiting for RCU readers; first->fib6_siblings.next then still points into the old ring and this softirq-side walker never reaches &first->fib6_siblings as its terminator. fib6_purge_rt() always WRITE_ONCE()s first->fib6_nsiblings to 0 before list_del_rcu(), so an inside-loop check is a reliable detach signal. [1] https://sashiko.dev/#/patchset/20260526020227.4857-1-jiayuan.chen%40linux.dev

    Source: suse_csaf, Ubuntu Security Notices, HKCERT (CC BY 3.0 HK) · HKCERT rating: medium, cvelistv5, NVD (NIST), 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
    • 6.11.11 – < 6.12
    • 6.13 – < 6.18.35
    • 6.12.2 – < 6.12.93
    • 6.19 – < 7.0.12
    • 6.1.128 – < 6.1.176
    • —
    • 6.6.75 – < 6.6.143
    • 6.12
    • 6.18.35
    • 6.12.93
    • 7.0.12
    • 6.1.176
    • 7.1
    • 6.6.143

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxubuntulinuxnoble
    Linuxubuntulinux-awsnoble
    Linuxubuntulinux-aws-6.8jammy
    Linuxubuntulinux-aws-fipsnoble
    Linuxubuntulinux-azurenoble
    Linuxubuntulinux-azure-6.8jammy
    Linuxubuntulinux-azure-fdenoble
    Linuxubuntulinux-azure-fde-6.8jammy
    Linuxubuntulinux-azure-fipsnoble
    Linuxubuntulinux-fipsnoble
    Linuxubuntulinux-gcpnoble
    Linuxubuntulinux-gcp-6.8jammy
    Linuxubuntulinux-gcp-fipsnoble
    Linuxubuntulinux-gkenoble
    Linuxubuntulinux-gkeopnoble
    Linuxubuntulinux-ibmnoble
    Linuxubuntulinux-ibm-6.8jammy
    Linuxubuntulinux-lowlatencynoble
    Linuxubuntulinux-lowlatency-hwe-6.8jammy
    Linuxubuntulinux-nvidianoble
    Linuxubuntulinux-nvidia-6.8jammy
    Linuxubuntulinux-nvidia-lowlatencynoble
    Linuxubuntulinux-oraclenoble
    Linuxubuntulinux-realtimenoble

    Weakness classes (CWE)

    • CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')

      Base

      The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.

      Entry at MITRE CWE-835

    • CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')

      Base

      The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.

      Entry at MITRE CWE-835

    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. Initial analysis by NVDNVD

      Newly listed as affected:
      • Linux Kernel (6.11.11 – before 6.12; 6.13 – before 6.18.35; 6.19 – before 7.0.12; 6.1.128 – before 6.1.176; 6.12.2 – before 6.12.93; 6.6.75 – before 6.6.143; 5 individual versions)

      Weakness type: CWE-835

      Show 8 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Weakness type (CWE)added
      —
      CWE-835
      Product configurationadded
      —
      OR *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.11.11 up to (excluding) 6.12 *cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.13 up to (excluding) 6.18.35 *cpe:2.3:o:linux:linux_kernel:7.1:rc5:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.19 up to (excluding) 7.0.12 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.1.128 up to (excluding) 6.1.176 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.12.2 up to (excluding) 6.12.93 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.6.75 up to (excluding) 6.6.143
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/0f7b73c3452635de83b8711b31abdda8e49aad7b Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/3948a7d92f7678e89e1776bb2d169afcad63b1ae Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/9b9d5bd6e3d4c9cecab5407604b690684b2532d2 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/9c7da87c2dc860bb17ca1ece942495d28b1ce3b9 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/ab9a10969a907b472a0196d999c08ff7144172e3 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/c87cd3cb309634bc8f50a54e2079424f219ac21f Types: Patch

      Source identifier: nvd@nist.gov

    2. Record modifiedCISA ADP

      Weakness type: CWE-835

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Weakness type (CWE)added
      —
      CWE-835

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

    3. Record modifiedLinux

      Show 12 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://git.kernel.org/stable/c/0f7b73c3452635de83b8711b31abdda8e49aad7b
      Referenceadded
      —
      https://git.kernel.org/stable/c/3948a7d92f7678e89e1776bb2d169afcad63b1ae
      Referenceadded
      —
      https://git.kernel.org/stable/c/9b9d5bd6e3d4c9cecab5407604b690684b2532d2
      Referenceadded
      —
      https://git.kernel.org/stable/c/9c7da87c2dc860bb17ca1ece942495d28b1ce3b9
      Referenceadded
      —
      https://git.kernel.org/stable/c/ab9a10969a907b472a0196d999c08ff7144172e3
      Referenceadded
      —
      https://git.kernel.org/stable/c/c87cd3cb309634bc8f50a54e2079424f219ac21f
      Referenceremoved
      https://git.kernel.org/stable/c/0f7b73c3452635de83b8711b31abdda8e49aad7b
      —
      Referenceremoved
      https://git.kernel.org/stable/c/3948a7d92f7678e89e1776bb2d169afcad63b1ae
      —
      Referenceremoved
      https://git.kernel.org/stable/c/9b9d5bd6e3d4c9cecab5407604b690684b2532d2
      —
      Referenceremoved
      https://git.kernel.org/stable/c/9c7da87c2dc860bb17ca1ece942495d28b1ce3b9
      —
      Referenceremoved
      https://git.kernel.org/stable/c/ab9a10969a907b472a0196d999c08ff7144172e3
      —
      Referenceremoved
      https://git.kernel.org/stable/c/c87cd3cb309634bc8f50a54e2079424f219ac21f
      —

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

    4. 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-2026-63968","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"yes"},{"technicalImpact":"partial"}],"version":"2.0.3","timestamp":"2026-10-16T15:34:13.232918Z"}

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

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