MediumCVE-2026-53263

    Linux Kernel: security vulnerability (CVE-2026-53263)

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

    What is affected, what to do

    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 4.6..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

    5.5

    Priority

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

    Source: NVD, CVSS v3

    5.5

    CVSS v3

    Severity Medium on the scale from 0 to 10.

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

    0.1 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 1.7

    Show all metrics
    Severity
    Medium
    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
    47.04 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
    5.5 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
    5.5
    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
    0.1 %
    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
    1.7
    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:

    6lowpan: fix off-by-one in multicast context address compression

    The second memcpy in lowpan_iphc_mcast_ctx_addr_compress() uses &data[1] as destination and &ipaddr->s6_addr[11] as source, but both should be offset by one: &data[2] and &ipaddr->s6_addr[12] respectively.

    This off-by-one has two consequences:

    1. data[1] is overwritten with s6_addr[11], corrupting the RIID field in the compressed multicast address
    2. data[5] is never written, so uninitialized kernel stack memory is transmitted over the network via lowpan_push_hc_data(), leaking kernel stack contents

    The correct inline data layout must match what the decompression function lowpan_uncompress_multicast_ctx_daddr() expects: data[0..1] = s6_addr[1..2] (flags/scope + RIID) data[2..5] = s6_addr[12..15] (group ID)

    Also zero-initialize the data array as a defensive measure against similar bugs in the future.

    Source: suse_csaf, Debian LTS Advisories, Ubuntu Security Notices, BSI WID Portal, BSI CSAF, siemens_advisory, NVD (NIST), CVE.org (MITRE), cvelistv5, 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
    • 6.7 – < 6.12.94
    • 6.13 – < 6.18.36
    • 5.11 – < 5.15.210
    • 4.6 – < 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
    Linuxdebianlinuxbookworm
    Linuxdebianlinuxbullseye
    Linuxdebianlinux-6.1bullseye
    Linuxubuntulinux-oracle-7.0noble
    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 modifiedLinux

      Show 24 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://git.kernel.org/stable/c/06ce6fc106b16dec9b535950db626261be865e5b
      Referenceadded
      —
      https://git.kernel.org/stable/c/2a58899d11009bffc7b4b32a571858f381121837
      Referenceadded
      —
      https://git.kernel.org/stable/c/4485d79617520d84ba5a14515e2b5136007d6deb
      Referenceadded
      —
      https://git.kernel.org/stable/c/c32f30ef5e66adbfa102348e2e8a23776eb007cb
      Referenceadded
      —
      https://git.kernel.org/stable/c/da8808463882c3f3c357b072e25053c2121f1419
      Referenceadded
      —
      https://git.kernel.org/stable/c/da8cbb64b47e9066b40af0de170901caf17b768c
      Referenceadded
      —
      https://git.kernel.org/stable/c/dcb1bec1c32ee5c3878354e087cf5dbee2b7c7af
      Referenceadded
      —
      https://git.kernel.org/stable/c/f24a58c72a45f4c109f3557a760cc4b60b7a6037
      Referenceremoved
      https://git.kernel.org/stable/c/06ce6fc106b16dec9b535950db626261be865e5b
      —
      Referenceremoved
      https://git.kernel.org/stable/c/2a58899d11009bffc7b4b32a571858f381121837
      —
      Referenceremoved
      https://git.kernel.org/stable/c/4485d79617520d84ba5a14515e2b5136007d6deb
      —
      Referenceremoved
      https://git.kernel.org/stable/c/c32f30ef5e66adbfa102348e2e8a23776eb007cb
      —
      Referenceremoved
      https://git.kernel.org/stable/c/da8808463882c3f3c357b072e25053c2121f1419
      —
      Referenceremoved
      https://git.kernel.org/stable/c/da8cbb64b47e9066b40af0de170901caf17b768c
      —
      Referenceremoved
      https://git.kernel.org/stable/c/dcb1bec1c32ee5c3878354e087cf5dbee2b7c7af
      —
      Referenceremoved
      https://git.kernel.org/stable/c/f24a58c72a45f4c109f3557a760cc4b60b7a6037
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/06ce6fc106b16dec9b535950db626261be865e5b Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/2a58899d11009bffc7b4b32a571858f381121837 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/4485d79617520d84ba5a14515e2b5136007d6deb Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/c32f30ef5e66adbfa102348e2e8a23776eb007cb Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/da8808463882c3f3c357b072e25053c2121f1419 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/da8cbb64b47e9066b40af0de170901caf17b768c Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/dcb1bec1c32ee5c3878354e087cf5dbee2b7c7af Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/f24a58c72a45f4c109f3557a760cc4b60b7a6037 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/2026/53xxx/CVE-2026-53263.json">CVE-2026-53263</a>
      Referenceadded
      —
      https://cert-portal.siemens.com/productcert/html/ssa-784472.html

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

    3. 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; 6.13 – before 6.18.36; 6.7 – before 6.12.94; 6.19 – before 7.0.13; 4.6 – before 5.10.259; 6 individual versions)

      CVSS V3.1: AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

      Weakness type: CWE-193

      Show 11 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      CVSSadded
      —
      AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
      Weakness type (CWE)added
      —
      CWE-193
      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) 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:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 4.6 up to (excluding) 5.10.259
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/06ce6fc106b16dec9b535950db626261be865e5b Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/2a58899d11009bffc7b4b32a571858f381121837 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/4485d79617520d84ba5a14515e2b5136007d6deb Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/c32f30ef5e66adbfa102348e2e8a23776eb007cb Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/da8808463882c3f3c357b072e25053c2121f1419 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/da8cbb64b47e9066b40af0de170901caf17b768c Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/dcb1bec1c32ee5c3878354e087cf5dbee2b7c7af Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/f24a58c72a45f4c109f3557a760cc4b60b7a6037 Types: Patch

      Source identifier: nvd@nist.gov

    Embed badge

    Show the severity and KEV status of this vulnerability on your site – with a link back here. The image is updated hourly.

    Badge preview for CVE-2026-53263
    <a href="https://intel.neosec.eu/en/cve/CVE-2026-53263"><img src="https://intel.neosec.eu/badge/cve/CVE-2026-53263.svg?lang=en" alt="CVE-2026-53263 – NEOSEC Intel" height="20"></a>