HighCVE-2026-45843

    Linux Kernel: security vulnerability (CVE-2026-45843)

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

    What is affected, what to do

    In the Linux kernel, the following vulnerability has been resolved: slip: bound decode() reads against the compressed packet length slhc_uncompress() parses a VJ-compressed TCP header by advancing a pointer through the packet via decode() and pull16(). Neither helper bounds-checks against isize, and decode() masks its return with & 0xffff so it can never return the -1 that callers test for -- those error paths are dead code.

    Update Linux Kernel to version 5.10.258, Linux Kernel to version 5.15.209, Linux Kernel to version 6.1.175.

    Affected
    • Linux Kernel lt 2.6.12..5.10.258
    • Linux Kernel lt 5.11..5.15.209
    • Linux Kernel lt 5.16..6.1.175
    • Linux Kernel lt 6.2..6.6.141
    • Linux Kernel lt 6.7..6.12.91
    • Linux Kernel lt 6.13..6.18.33
    • Linux Kernel lt 6.19..7.0.10
    Fixed in
    • Linux Kernel 5.10.258
    • Linux Kernel 5.15.209
    • Linux Kernel 6.1.175
    • Linux Kernel 6.6.141
    • Linux Kernel 6.12.91
    • Linux Kernel 6.18.33
    • Linux Kernel 7.0.10
    • Linux Kernel 7.1

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

    Metrics

    8.2

    Priority

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

    Source: Vendor (CNA), CVSS v3

    8.2

    CVSS v3

    Severity High on the scale from 0 to 10.

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

    0.4 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 34.0

    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
    68.20 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
    8.2 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
    8.2
    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
    34.0
    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
    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-126

    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: slip: bound decode() reads against the compressed packet length slhc_uncompress() parses a VJ-compressed TCP header by advancing a pointer through the packet via decode() and pull16(). Neither helper bounds-checks against isize, and decode() masks its return with & 0xffff so it can never return the -1 that callers test for -- those error paths are dead code. A short compressed frame whose change byte requests optional fields lets decode() read past the end of the packet. The over-read bytes are folded into the cached cstate and reflected into subsequent reconstructed packets. Make decode() and pull16() take the packet end pointer and return -1 when exhausted. Add a bounds check before the TCP-checksum read. The existing == -1 tests now do what they were always meant to.

    Source: Debian LTS Advisories, suse_csaf, Ubuntu Security Notices, siemens_advisory, Debian Security Advisories, cvelistv5, NVD (NIST), Microsoft Security Update Guide, ENISA EUVD, 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
    • 5.16 – < 6.1.175
    • 5.11 – < 5.15.209
    • 2.6.12 – < 5.10.258
    • 6.7 – < 6.12.91
    • —
    • 6.13 – < 6.18.33
    • 6.2 – < 6.6.141
    • 6.19 – < 7.0.10
    • 6.1.175
    • 5.15.209
    • 5.10.258
    • 6.12.91
    • 7.1
    • 6.18.33
    • 6.6.141
    • 7.0.10
    SiemensSIMATIC S7
    • 1500 TM MFP V1.1.1 GNU/Linux subsystem
    • —

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebianlinuxbookworm
    Linuxdebianlinuxbullseye
    Linuxdebianlinuxtrixie
    Linuxdebianlinux-6.1bullseye
    Linuxlinuxlinux_kernel2.6.12
    Linuxlinuxlinux_kernel—

    Weakness classes (CWE)

    • CWE-126Buffer Over-read

      Variant

      The product reads from a buffer using buffer access mechanisms such as indexes or pointers that reference memory locations after the targeted buffer.

      Entry at MITRE CWE-126

    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-126

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Weakness type (CWE)added
      —
      CWE-126

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

    2. 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-2026-45843","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"yes"},{"technicalImpact":"partial"}],"version":"2.0.3","timestamp":"2026-10-16T15:17:54.838787Z"}

      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/0511ecb00e61bf28e2fec4bb41fcce385c3a3b2d
      Referenceadded
      —
      https://git.kernel.org/stable/c/335957df4ed60f02a2ec0432fbedbf0cc7241d8b
      Referenceadded
      —
      https://git.kernel.org/stable/c/37537e42e6df387398bee85cb85070cc80bb1e10
      Referenceadded
      —
      https://git.kernel.org/stable/c/4c1367a2d7aad643a6f87c6931b13cc1a25e8ca7
      Referenceadded
      —
      https://git.kernel.org/stable/c/4cefe32639933d652614b0bd50f818f9af4af78f
      Referenceadded
      —
      https://git.kernel.org/stable/c/6268f01ae989013671b526c883e92655342c6f6f
      Referenceadded
      —
      https://git.kernel.org/stable/c/9aafba2f49e1fcccc2018816f5836a609c925879
      Referenceadded
      —
      https://git.kernel.org/stable/c/d42bec6e4f6d6d658be365539400b3314b76b2a7
      Referenceremoved
      https://git.kernel.org/stable/c/0511ecb00e61bf28e2fec4bb41fcce385c3a3b2d
      —
      Referenceremoved
      https://git.kernel.org/stable/c/335957df4ed60f02a2ec0432fbedbf0cc7241d8b
      —
      Referenceremoved
      https://git.kernel.org/stable/c/37537e42e6df387398bee85cb85070cc80bb1e10
      —
      Referenceremoved
      https://git.kernel.org/stable/c/4c1367a2d7aad643a6f87c6931b13cc1a25e8ca7
      —
      Referenceremoved
      https://git.kernel.org/stable/c/4cefe32639933d652614b0bd50f818f9af4af78f
      —
      Referenceremoved
      https://git.kernel.org/stable/c/6268f01ae989013671b526c883e92655342c6f6f
      —
      Referenceremoved
      https://git.kernel.org/stable/c/9aafba2f49e1fcccc2018816f5836a609c925879
      —
      Referenceremoved
      https://git.kernel.org/stable/c/d42bec6e4f6d6d658be365539400b3314b76b2a7
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/0511ecb00e61bf28e2fec4bb41fcce385c3a3b2d Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/335957df4ed60f02a2ec0432fbedbf0cc7241d8b Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/37537e42e6df387398bee85cb85070cc80bb1e10 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/4c1367a2d7aad643a6f87c6931b13cc1a25e8ca7 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/4cefe32639933d652614b0bd50f818f9af4af78f Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/6268f01ae989013671b526c883e92655342c6f6f Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/9aafba2f49e1fcccc2018816f5836a609c925879 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/d42bec6e4f6d6d658be365539400b3314b76b2a7 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/2026/45xxx/CVE-2026-45843.json">CVE-2026-45843</a>
      Referenceadded
      —
      https://cert-portal.siemens.com/productcert/html/ssa-784472.html

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

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