HighCVE-2026-53212

    Linux Kernel: Use After Free (CVE-2026-53212)

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

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    What is affected, what to do

    In the Linux kernel, the following vulnerability has been resolved: netfilter: nft_tunnel: fix use-after-free on object destroy nft_tunnel_obj_destroy() calls metadata_dst_free() which directly kfree()s the metadata_dst, ignoring the dst_entry refcount. Packets that took a reference via dst_hold() in nft_tunnel_obj_eval() and are still queued (e.g. in a netem qdisc) are left with a dangling pointer.

    Update Linux Kernel to version 5.10.259, Linux Kernel to version 5.15.210, Linux Kernel to version 6.1.176.

    Affected
    • Linux Kernel lt 4.19..5.10.259
    • Linux Kernel lt 5.11..5.15.210
    • Linux Kernel lt 5.16..6.1.176
    • Linux Kernel lt 6.2..6.6.143
    • Linux Kernel lt 6.7..6.12.94
    • Linux Kernel lt 6.13..6.18.36
    • Linux Kernel lt 6.19..7.0.13
    Fixed in
    • Linux Kernel 5.10.259
    • Linux Kernel 5.15.210
    • Linux Kernel 6.1.176
    • Linux Kernel 6.6.143
    • Linux Kernel 6.12.94
    • Linux Kernel 6.18.36
    • Linux Kernel 7.0.13
    • Linux Kernel 7.1

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

    Metrics

    7.8

    Priority

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

    Source: Vendor (CNA), CVSS v3

    7.8

    CVSS v3

    Severity High on the scale from 0 to 10.

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

    0.2 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 9.1

    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
    58.86 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
    7.8 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
    7.8
    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
    0.2 %
    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
    9.1
    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
    CISA assessment (SSVC)
    Exploitation: none known · not 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-416

    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_tunnel: fix use-after-free on object destroy nft_tunnel_obj_destroy() calls metadata_dst_free() which directly kfree()s the metadata_dst, ignoring the dst_entry refcount. Packets that took a reference via dst_hold() in nft_tunnel_obj_eval() and are still queued (e.g. in a netem qdisc) are left with a dangling pointer. When these packets are eventually dequeued, dst_release() operates on freed memory. Replace metadata_dst_free() with dst_release() so the metadata_dst is freed only after all references are dropped. The dst subsystem already handles metadata_dst cleanup in dst_destroy() when DST_METADATA is set.

    Source: suse_csaf, Ubuntu Security Notices, Debian LTS Advisories, BSI WID Portal, BSI CSAF, siemens_advisory, Microsoft Security Update Guide, cvelistv5, NVD (NIST), 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
    • 6.7 – < 6.12.94
    • 6.13 – < 6.18.36
    • 5.11 – < 5.15.210
    • 4.19 – < 5.10.259
    • —
    • 5.16 – < 6.1.176
    • 6.19 – < 7.0.13
    • 6.2 – < 6.6.143
    • 6.12.94
    • 6.18.36
    • 5.15.210
    • 5.10.259
    • 7.1
    • 6.1.176
    • 7.0.13
    • 6.6.143
    SiemensSIMATIC S7
    • 1500 TM MFP V1.1.1 GNU/Linux subsystem
    • —

    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-416Use After Free

      Variant

      The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

      Entry at MITRE CWE-416

    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-416

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Weakness type (CWE)added
      —
      CWE-416

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

    2. Record modifiedCISA ADP

      CISA assessment (SSVC): exploitation: none known, automatable: no

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      SSVC assessmentadded
      —
      {"id":"CVE-2026-53212","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:26:56.855594Z"}

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

    3. Record modifiedLinux

      Show 24 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://git.kernel.org/stable/c/349df61526d2e39decc685d246202e3e284cfe05
      Referenceadded
      —
      https://git.kernel.org/stable/c/55b79b1ae42372012413ce0413181d26679b17ef
      Referenceadded
      —
      https://git.kernel.org/stable/c/5e9ee18b27fde88cb6148202b33916c66693fe82
      Referenceadded
      —
      https://git.kernel.org/stable/c/8767fe4079affa74314d7eb3220e700150289842
      Referenceadded
      —
      https://git.kernel.org/stable/c/941d7394efda5e054e2d6f3e0dd0f6a9ba19aaa3
      Referenceadded
      —
      https://git.kernel.org/stable/c/c32b26aaa2f9216520a38b3f4bfeec846eb3eb8a
      Referenceadded
      —
      https://git.kernel.org/stable/c/f9a0e4b61054cde89a2a77845293c726cc07cc43
      Referenceadded
      —
      https://git.kernel.org/stable/c/fda6573a46ad24f35348e024905ee5bdf729797e
      Referenceremoved
      https://git.kernel.org/stable/c/349df61526d2e39decc685d246202e3e284cfe05
      —
      Referenceremoved
      https://git.kernel.org/stable/c/55b79b1ae42372012413ce0413181d26679b17ef
      —
      Referenceremoved
      https://git.kernel.org/stable/c/5e9ee18b27fde88cb6148202b33916c66693fe82
      —
      Referenceremoved
      https://git.kernel.org/stable/c/8767fe4079affa74314d7eb3220e700150289842
      —
      Referenceremoved
      https://git.kernel.org/stable/c/941d7394efda5e054e2d6f3e0dd0f6a9ba19aaa3
      —
      Referenceremoved
      https://git.kernel.org/stable/c/c32b26aaa2f9216520a38b3f4bfeec846eb3eb8a
      —
      Referenceremoved
      https://git.kernel.org/stable/c/f9a0e4b61054cde89a2a77845293c726cc07cc43
      —
      Referenceremoved
      https://git.kernel.org/stable/c/fda6573a46ad24f35348e024905ee5bdf729797e
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/349df61526d2e39decc685d246202e3e284cfe05 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/55b79b1ae42372012413ce0413181d26679b17ef Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/5e9ee18b27fde88cb6148202b33916c66693fe82 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/8767fe4079affa74314d7eb3220e700150289842 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/941d7394efda5e054e2d6f3e0dd0f6a9ba19aaa3 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/c32b26aaa2f9216520a38b3f4bfeec846eb3eb8a Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/f9a0e4b61054cde89a2a77845293c726cc07cc43 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/fda6573a46ad24f35348e024905ee5bdf729797e Types: Patch
      —

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

    4. 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/2026/53xxx/CVE-2026-53212.json">CVE-2026-53212</a>
      Referenceadded
      —
      https://cert-portal.siemens.com/productcert/html/ssa-784472.html

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

    5. Initial analysis by NVDNVD

      Newly listed as affected:
      • Linux Kernel (5.16 – before 6.1.176; 6.2 – before 6.6.143; 5.11 – before 5.15.210; 4.19 – before 5.10.259; 6.13 – before 6.18.36; 6.7 – before 6.12.94; 6.19 – before 7.0.13; 6 individual versions)

      Weakness type: CWE-416

      Show 10 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Weakness type (CWE)added
      —
      CWE-416
      Product configurationadded
      —
      OR *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) 5.16 up to (excluding) 6.1.176 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.2 up to (excluding) 6.6.143 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.11 up to (excluding) 5.15.210 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 4.19 up to (excluding) 5.10.259 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.13 up to (excluding) 6.18.36 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.7 up to (excluding) 6.12.94 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.19 up to (excluding) 7.0.13 *cpe:2.3:o:linux:linux_kernel:7.1:rc5:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc6:*:*:*:*:*:*
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/349df61526d2e39decc685d246202e3e284cfe05 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/55b79b1ae42372012413ce0413181d26679b17ef Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/5e9ee18b27fde88cb6148202b33916c66693fe82 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/8767fe4079affa74314d7eb3220e700150289842 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/941d7394efda5e054e2d6f3e0dd0f6a9ba19aaa3 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/c32b26aaa2f9216520a38b3f4bfeec846eb3eb8a Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/f9a0e4b61054cde89a2a77845293c726cc07cc43 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/fda6573a46ad24f35348e024905ee5bdf729797e Types: Patch

      Source identifier: nvd@nist.gov

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