MediumCVE-2026-31411

    Linux Kernel: security vulnerability (CVE-2026-31411)

    Published Last modified Sources: Siemens ProductCERT, Debian LTS, Ubuntu, Debian, BSI, SUSE, Red Hat, EUVD, CVE.org

    Share

    What is affected, what to do

    In the Linux kernel, the following vulnerability has been resolved: net: atm: fix crash due to unvalidated vcc pointer in sigd_send() Reproducer available at [1]. The ATM send path (sendmsg -> vcc_sendmsg -> sigd_send) reads the vcc pointer from msg->vcc and uses it directly without any validation.

    Update Linux Kernel to version 5.10.252, Linux Kernel to version 5.15.202, Linux Kernel to version 6.1.165.

    Affected
    • Linux Kernel lt 2.6.12..5.10.252
    • Linux Kernel lt 5.11..5.15.202
    • Linux Kernel lt 5.16..6.1.165
    • Linux Kernel lt 6.2..6.6.128
    • Linux Kernel lt 6.7..6.12.75
    • Linux Kernel lt 6.13..6.18.14
    • Linux Kernel lt 6.19..6.19.4
    • Linux Kernel lt 6.20..7.0
    Fixed in
    • Linux Kernel 5.10.252
    • Linux Kernel 5.15.202
    • Linux Kernel 6.1.165
    • Linux Kernel 6.6.128
    • Linux Kernel 6.12.75
    • Linux Kernel 6.18.14
    • Linux Kernel 6.19.4
    • Linux Kernel 7.0

    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: Siemens ProductCERT, Debian LTS, Ubuntu, Debian, BSI, SUSE, Red Hat, EUVD, CVE.org

    0.1 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 2.9

    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
    43.28 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
    2.9
    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: partial
    Source: CISA Vulnrichment, as of 5 November 2026

    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: net: atm: fix crash due to unvalidated vcc pointer in sigd_send() Reproducer available at [1]. The ATM send path (sendmsg -> vcc_sendmsg -> sigd_send) reads the vcc pointer from msg->vcc and uses it directly without any validation. This pointer comes from userspace via sendmsg() and can be arbitrarily forged: int fd = socket(AF_ATMSVC, SOCK_DGRAM, 0); ioctl(fd, ATMSIGD_CTRL); // become ATM signaling daemon struct msghdr msg = { .msg_iov = &iov, ... }; *(unsigned long *)(buf + 4) = 0xdeadbeef; // fake vcc pointer sendmsg(fd, &msg, 0); // kernel dereferences 0xdeadbeef In normal operation, the kernel sends the vcc pointer to the signaling daemon via sigd_enq() when processing operations like connect(), bind(), or listen(). The daemon is expected to return the same pointer when responding. However, a malicious daemon can send arbitrary pointer values. Fix this by introducing find_get_vcc() which validates the pointer by searching through vcc_hash (similar to how sigd_close() iterates over all VCCs), and acquires a reference via sock_hold() if found. Since struct atm_vcc embeds struct sock as its first member, they share the same lifetime. Therefore using sock_hold/sock_put is sufficient to keep the vcc alive while it is being used. Note that there may be a race with sigd_close() which could mark the vcc with various flags (e.g., ATM_VF_RELEASED) after find_get_vcc() returns. However, sock_hold() guarantees the memory remains valid, so this race only affects the logical state, not memory safety. [1]: https://gist.github.com/mrpre/1ba5949c45529c511152e2f4c755b0f3

    Source: siemens_advisory, Debian LTS Advisories, Ubuntu Security Notices, Debian Security Advisories, BSI WID Portal, BSI CSAF, suse_csaf, redhat_csaf, ENISA EUVD, 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
    • 5.16 – < 6.1.165
    • 6.7 – < 6.12.75
    • 6.19 – < 6.19.4
    • 2.6.12 – < 5.10.252
    • 6.20 – < 7.0
    • 5.11 – < 5.15.202
    • 6.2 – < 6.6.128
    • 6.13 – < 6.18.14
    • 6.1.165
    • 6.12.75
    • 6.19.4
    • 5.10.252
    • 7.0
    • 5.15.202
    • 6.6.128
    • 6.18.14
    IBMDataPower Gateway
    • < 11.0.0.3
    • < 10.6.0.11
    • < 10.5.0.23
    • 11.0.0.3
    • 10.6.0.11
    • 10.5.0.23
    IBMQRadar SIEM
    • <7.5.0 UP15 IF06
    • —
    Open SourceLinux Kernel
    • < 5.15.202
    • < 6.6.128
    • < 6.18.14
    • < 6.19.4
    • < 6.1.165
    • < 7.0-rc1
    • < 5.10.252
    • < 6.12.75
    • 5.15.202
    • 6.6.128
    • 6.18.14
    • 6.19.4
    • 6.1.165
    • 7.0-rc1
    • 5.10.252
    • 6.12.75

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebianlinuxbookworm
    Linuxdebianlinuxbullseye
    Linuxdebianlinuxtrixie
    Linuxdebianlinux-6.1bullseye
    Linuxlinuxlinux_kernel2.6.12
    Linuxlinuxlinux_kernel7.0
    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

      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-2026-31411","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"partial"}],"version":"2.0.3","timestamp":"2026-11-05T21:32:20.180916Z"}

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

    2. Record modifiedLinux

      Show 24 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://git.kernel.org/stable/c/1c8bda3df028d5e54134077dcd09f46ca8cfceb5
      Referenceadded
      —
      https://git.kernel.org/stable/c/21c303fec138c002f90ed33bce60e807d53072bb
      Referenceadded
      —
      https://git.kernel.org/stable/c/3e1a8b00095246a9a2b46b57f6d471c6d3c00ed2
      Referenceadded
      —
      https://git.kernel.org/stable/c/440c9a5fc477a8ee259d8bf669531250b8398651
      Referenceadded
      —
      https://git.kernel.org/stable/c/69d3f9ee5489e6e8b66defcfa226e91d82393297
      Referenceadded
      —
      https://git.kernel.org/stable/c/ae88a5d2f29b69819dc7b04086734439d074a643
      Referenceadded
      —
      https://git.kernel.org/stable/c/c96549d07dfdd51aadf0722cfb40711574424840
      Referenceadded
      —
      https://git.kernel.org/stable/c/e3f80666c2739296c3b69a127300455c43aa1067
      Referenceremoved
      https://git.kernel.org/stable/c/1c8bda3df028d5e54134077dcd09f46ca8cfceb5
      —
      Referenceremoved
      https://git.kernel.org/stable/c/21c303fec138c002f90ed33bce60e807d53072bb
      —
      Referenceremoved
      https://git.kernel.org/stable/c/3e1a8b00095246a9a2b46b57f6d471c6d3c00ed2
      —
      Referenceremoved
      https://git.kernel.org/stable/c/440c9a5fc477a8ee259d8bf669531250b8398651
      —
      Referenceremoved
      https://git.kernel.org/stable/c/69d3f9ee5489e6e8b66defcfa226e91d82393297
      —
      Referenceremoved
      https://git.kernel.org/stable/c/ae88a5d2f29b69819dc7b04086734439d074a643
      —
      Referenceremoved
      https://git.kernel.org/stable/c/c96549d07dfdd51aadf0722cfb40711574424840
      —
      Referenceremoved
      https://git.kernel.org/stable/c/e3f80666c2739296c3b69a127300455c43aa1067
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/1c8bda3df028d5e54134077dcd09f46ca8cfceb5 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/21c303fec138c002f90ed33bce60e807d53072bb Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/3e1a8b00095246a9a2b46b57f6d471c6d3c00ed2 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/440c9a5fc477a8ee259d8bf669531250b8398651 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/69d3f9ee5489e6e8b66defcfa226e91d82393297 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/ae88a5d2f29b69819dc7b04086734439d074a643 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/c96549d07dfdd51aadf0722cfb40711574424840 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/e3f80666c2739296c3b69a127300455c43aa1067 Types: Patch
      —

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

    3. Record modifiedSiemens ADP

      Show 6 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/31xxx/CVE-2026-31411.json">CVE-2026-31411</a>
      Referenceadded
      —
      https://cert-portal.siemens.com/productcert/html/ssa-019113.html
      Referenceadded
      —
      https://cert-portal.siemens.com/productcert/html/ssa-082556.html
      Referenceadded
      —
      https://cert-portal.siemens.com/productcert/html/ssa-457936.html
      Referenceremoved
      https://cert-portal.siemens.com/productcert/html/ssa-019113.html
      —
      Referenceremoved
      https://cert-portal.siemens.com/productcert/html/ssa-082556.html
      —

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

    One NVD translation into another language is hidden.

    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-2026-31411
    <a href="https://intel.neosec.eu/en/cve/CVE-2026-31411"><img src="https://intel.neosec.eu/badge/cve/CVE-2026-31411.svg?lang=en" alt="CVE-2026-31411 – NEOSEC Intel" height="20"></a>