HighCVE-2026-46064

    Linux Kernel: security vulnerability (CVE-2026-46064)

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

    What is affected, what to do

    In the Linux kernel, the following vulnerability has been resolved: ibmasm: fix heap over-read in ibmasm_send_i2o_message() The ibmasm_send_i2o_message() function uses get_dot_command_size() to compute the byte count for memcpy_toio(), but this value is derived from user-controlled fields in the dot_command_header (command_size: u8, data_size: u16) and is never validated against the actual allocation size. A root user can write a small buffer with inflated header fields, causing memcpy_toio() to read up to ~65 KB past the end of the allocation into adjacent kernel heap, which is then forwarded to the service processor over MMIO.

    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..6.6.140
    • Linux Kernel lt 6.7..6.12.86
    • Linux Kernel lt 6.13..6.18.27
    • Linux Kernel lt 6.19..7.0.4
    Fixed in
    • Linux Kernel 5.10.258
    • Linux Kernel 5.15.209
    • Linux Kernel 6.1.175
    • Linux Kernel 6.6.140
    • Linux Kernel 6.12.86
    • Linux Kernel 6.18.27
    • Linux Kernel 7.0.4
    • Linux Kernel 7.1

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

    Metrics

    7.1

    Priority

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

    Source: NVD, CVSS v3

    7.1

    CVSS v3

    Severity High on the scale from 0 to 10.

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

    0.1 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 3.5

    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
    53.61 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
    7.1 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
    7.1
    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
    3.5
    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
    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: ibmasm: fix heap over-read in ibmasm_send_i2o_message() The ibmasm_send_i2o_message() function uses get_dot_command_size() to compute the byte count for memcpy_toio(), but this value is derived from user-controlled fields in the dot_command_header (command_size: u8, data_size: u16) and is never validated against the actual allocation size. A root user can write a small buffer with inflated header fields, causing memcpy_toio() to read up to ~65 KB past the end of the allocation into adjacent kernel heap, which is then forwarded to the service processor over MMIO. Silently clamping the copy size is not sufficient: if the header fields claim a larger size than the buffer, the SP receives a dot command whose own header is inconsistent with the I2O message length, which can cause the SP to desynchronize. Reject such commands outright by returning failure. Validate command_size before calling get_mfa_inbound() to avoid leaking an I2O message frame: reading INBOUND_QUEUE_PORT dequeues a hardware frame from the controller's free pool, and returning without a corresponding set_mfa_inbound() call would permanently exhaust it. Additionally, clamp command_size to I2O_COMMAND_SIZE before the memcpy_toio() so the MMIO write stays within the I2O message frame, consistent with the clamping already performed by outgoing_message_size() for the header field.

    Source: suse_csaf, Debian LTS Advisories, Ubuntu Security Notices, siemens_advisory, BSI WID Portal, BSI CSAF, NVD (NIST), ENISA EUVD, 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
    • 5.16 – < 6.1.175
    • 6.19 – < 7.0.4
    • 6.2 – < 6.6.140
    • 6.13 – < 6.18.27
    • 5.11 – < 5.15.209
    • 2.6.12 – < 5.10.258
    • —
    • 6.7 – < 6.12.86
    • 6.1.175
    • 7.0.4
    • 6.6.140
    • 6.18.27
    • 5.15.209
    • 5.10.258
    • 7.1
    • 6.12.86
    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
    Linuxlinuxlinux_kernel2.6.12
    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/9aad71144fa3682cca3837a06c8623016790e7ec
      Referenceadded
      —
      https://git.kernel.org/stable/c/9e8f6c9d4ecddda2f28baa1678340286cff3969c
      Referenceadded
      —
      https://git.kernel.org/stable/c/b870f652877bfbe321bd0f4096fc37a93296f7b6
      Referenceadded
      —
      https://git.kernel.org/stable/c/c1c2417c60dbdca5ebb00462f21ee71c2d7f7083
      Referenceadded
      —
      https://git.kernel.org/stable/c/ca1c857e2bb74a9fc0606128334f85316d57067b
      Referenceadded
      —
      https://git.kernel.org/stable/c/ce57fa439bd1b5d664f334a0c3e3f0e42abb0153
      Referenceadded
      —
      https://git.kernel.org/stable/c/fd19eb1c75047a4ed4e855f56cafd704dc3914e0
      Referenceadded
      —
      https://git.kernel.org/stable/c/fe31722b0194ff76bf8b461e8bf97a2081147787
      Referenceremoved
      https://git.kernel.org/stable/c/9aad71144fa3682cca3837a06c8623016790e7ec
      —
      Referenceremoved
      https://git.kernel.org/stable/c/9e8f6c9d4ecddda2f28baa1678340286cff3969c
      —
      Referenceremoved
      https://git.kernel.org/stable/c/b870f652877bfbe321bd0f4096fc37a93296f7b6
      —
      Referenceremoved
      https://git.kernel.org/stable/c/c1c2417c60dbdca5ebb00462f21ee71c2d7f7083
      —
      Referenceremoved
      https://git.kernel.org/stable/c/ca1c857e2bb74a9fc0606128334f85316d57067b
      —
      Referenceremoved
      https://git.kernel.org/stable/c/ce57fa439bd1b5d664f334a0c3e3f0e42abb0153
      —
      Referenceremoved
      https://git.kernel.org/stable/c/fd19eb1c75047a4ed4e855f56cafd704dc3914e0
      —
      Referenceremoved
      https://git.kernel.org/stable/c/fe31722b0194ff76bf8b461e8bf97a2081147787
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/9aad71144fa3682cca3837a06c8623016790e7ec Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/9e8f6c9d4ecddda2f28baa1678340286cff3969c Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/b870f652877bfbe321bd0f4096fc37a93296f7b6 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/c1c2417c60dbdca5ebb00462f21ee71c2d7f7083 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/ca1c857e2bb74a9fc0606128334f85316d57067b Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/ce57fa439bd1b5d664f334a0c3e3f0e42abb0153 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/fd19eb1c75047a4ed4e855f56cafd704dc3914e0 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/fe31722b0194ff76bf8b461e8bf97a2081147787 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/2026/46xxx/CVE-2026-46064.json">CVE-2026-46064</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 (6.7 – before 6.12.86; 5.16 – before 6.1.175; 5.11 – before 5.15.209; 6.2 – before 6.6.140; 2.6.12.1 – before 5.10.258; 6.13 – before 6.18.27; 6.19 – before 7.0.4; 5 individual versions)

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

      Weakness type: CWE-125

      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:H/I:N/A:H
      Weakness type (CWE)added
      —
      CWE-125
      Product configurationadded
      —
      OR *cpe:2.3:o:linux:linux_kernel:2.6.12:rc4:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:2.6.12:rc5:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:2.6.12:rc2:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:2.6.12:rc3:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:2.6.12:-:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.7 up to (excluding) 6.12.86 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.16 up to (excluding) 6.1.175 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.11 up to (excluding) 5.15.209 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.2 up to (excluding) 6.6.140 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 2.6.12.1 up to (excluding) 5.10.258 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.13 up to (excluding) 6.18.27 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.19 up to (excluding) 7.0.4
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/9aad71144fa3682cca3837a06c8623016790e7ec Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/9e8f6c9d4ecddda2f28baa1678340286cff3969c Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/b870f652877bfbe321bd0f4096fc37a93296f7b6 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/c1c2417c60dbdca5ebb00462f21ee71c2d7f7083 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/ca1c857e2bb74a9fc0606128334f85316d57067b Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/ce57fa439bd1b5d664f334a0c3e3f0e42abb0153 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/fd19eb1c75047a4ed4e855f56cafd704dc3914e0 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/fe31722b0194ff76bf8b461e8bf97a2081147787 Types: Patch

      Source identifier: nvd@nist.gov

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