HighCVE-2026-46033

    Linux Kernel: Out-of-Bounds Access (CVE-2026-46033)

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

    What is affected, what to do

    In the Linux kernel, the following vulnerability has been resolved: crypto: authencesn - reject short ahash digests during instance creation authencesn requires either a zero authsize or an authsize of at least 4 bytes because the ESN encrypt/decrypt paths always move 4 bytes of high-order sequence number data at the end of the authenticated data. While crypto_authenc_esn_setauthsize() already rejects explicit non-zero authsizes in the range 1..3, crypto_authenc_esn_create() still copied auth->digestsize into inst->alg.maxauthsize without validating it.

    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 4.11..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, Siemens ProductCERT, Debian LTS, Ubuntu, BSI, CVE.org, Msrc Update Guide, EUVD

    0.1 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 3.1

    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
    53.59 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
    3.1
    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

    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: crypto: authencesn - reject short ahash digests during instance creation authencesn requires either a zero authsize or an authsize of at least 4 bytes because the ESN encrypt/decrypt paths always move 4 bytes of high-order sequence number data at the end of the authenticated data. While crypto_authenc_esn_setauthsize() already rejects explicit non-zero authsizes in the range 1..3, crypto_authenc_esn_create() still copied auth->digestsize into inst->alg.maxauthsize without validating it. The AEAD core then initialized the tfm's default authsize from that value. As a result, selecting an ahash with digest size 1..3, such as cbcmac(cipher_null), exposed authencesn instances whose default authsize was invalid even though setauthsize() would have rejected the same value. AF_ALG could then trigger the ESN tail handling with a too-short tag and hit an out-of-bounds access. Reject authencesn instances whose ahash digest size is in the invalid non-zero range 1..3 so that no tfm can inherit an unsupported default authsize.

    Source: suse_csaf, siemens_advisory, Debian LTS Advisories, Ubuntu Security Notices, BSI WID Portal, BSI CSAF, cvelistv5, NVD (NIST), CVE.org (MITRE), Microsoft Security Update Guide, ENISA EUVD

    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
    • 4.11 – < 5.10.258
    • 6.13 – < 6.18.27
    • 5.11 – < 5.15.209
    • —
    • 6.7 – < 6.12.86
    • 6.1.175
    • 7.0.4
    • 6.6.140
    • 5.10.258
    • 6.18.27
    • 5.15.209
    • 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_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 modifiedSiemens ADP

      Show 3 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/2026/46xxx/CVE-2026-46033.json">CVE-2026-46033</a>
      Referenceadded
      —
      https://cert-portal.siemens.com/productcert/html/ssa-457936.html
      Referenceadded
      —
      https://cert-portal.siemens.com/productcert/html/ssa-784472.html

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

    2. Record modifiedLinux

      Show 24 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://git.kernel.org/stable/c/2f31cd1e64a079c845bca31d2da7b3c90a311726
      Referenceadded
      —
      https://git.kernel.org/stable/c/5db6ef9847717329f12c5ea8aba7e9f588a980c0
      Referenceadded
      —
      https://git.kernel.org/stable/c/67f1f0933cc3d78dde222842bcad2778ec7a0b88
      Referenceadded
      —
      https://git.kernel.org/stable/c/77f59fb2d3aa33e90ec6cbbf45dcfb20ab82b1a9
      Referenceadded
      —
      https://git.kernel.org/stable/c/9aff81e8217e9de2929084b03b3c7f81988c112b
      Referenceadded
      —
      https://git.kernel.org/stable/c/b42821c15445f93daea3e76ada682b2b7181c476
      Referenceadded
      —
      https://git.kernel.org/stable/c/b69933e97efea238ebbfcf70c2b1be1cd03f13e3
      Referenceadded
      —
      https://git.kernel.org/stable/c/d4c6a6d08e70bb1083c7c405fc7faacbf19aebc0
      Referenceremoved
      https://git.kernel.org/stable/c/2f31cd1e64a079c845bca31d2da7b3c90a311726
      —
      Referenceremoved
      https://git.kernel.org/stable/c/5db6ef9847717329f12c5ea8aba7e9f588a980c0
      —
      Referenceremoved
      https://git.kernel.org/stable/c/67f1f0933cc3d78dde222842bcad2778ec7a0b88
      —
      Referenceremoved
      https://git.kernel.org/stable/c/77f59fb2d3aa33e90ec6cbbf45dcfb20ab82b1a9
      —
      Referenceremoved
      https://git.kernel.org/stable/c/9aff81e8217e9de2929084b03b3c7f81988c112b
      —
      Referenceremoved
      https://git.kernel.org/stable/c/b42821c15445f93daea3e76ada682b2b7181c476
      —
      Referenceremoved
      https://git.kernel.org/stable/c/b69933e97efea238ebbfcf70c2b1be1cd03f13e3
      —
      Referenceremoved
      https://git.kernel.org/stable/c/d4c6a6d08e70bb1083c7c405fc7faacbf19aebc0
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/2f31cd1e64a079c845bca31d2da7b3c90a311726 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/5db6ef9847717329f12c5ea8aba7e9f588a980c0 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/67f1f0933cc3d78dde222842bcad2778ec7a0b88 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/77f59fb2d3aa33e90ec6cbbf45dcfb20ab82b1a9 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/9aff81e8217e9de2929084b03b3c7f81988c112b Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/b42821c15445f93daea3e76ada682b2b7181c476 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/b69933e97efea238ebbfcf70c2b1be1cd03f13e3 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/d4c6a6d08e70bb1083c7c405fc7faacbf19aebc0 Types: Patch
      —

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

    3. Record modifiedRed Hat ADP

      Show 6 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://access.redhat.com/security/cve/CVE-2026-46033
      Referenceadded
      —
      https://bugzilla.redhat.com/show_bug.cgi?id=2482000
      Referenceadded
      —
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-46033.json
      Referenceremoved
      https://access.redhat.com/security/cve/CVE-2026-46033
      —
      Referenceremoved
      https://bugzilla.redhat.com/show_bug.cgi?id=2482000
      —
      Referenceremoved
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-46033.json
      —

      Source identifier: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

    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/2026/46xxx/CVE-2026-46033.json">CVE-2026-46033</a>
      Referenceadded
      —
      https://cert-portal.siemens.com/productcert/html/ssa-019113.html

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

    5. Record modifiedRed Hat ADP

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

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

      Show 2 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
      CVSSremoved
      AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
      —

      Source identifier: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

    Show one older change

    1. 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; 6.13 – before 6.18.27; 6.19 – before 7.0.4; 4.11 – before 5.10.258; 1 individual version)

      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:7.1:rc1:*:*:*:*:*:* *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) 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 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 4.11 up to (excluding) 5.10.258
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/2f31cd1e64a079c845bca31d2da7b3c90a311726 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/5db6ef9847717329f12c5ea8aba7e9f588a980c0 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/67f1f0933cc3d78dde222842bcad2778ec7a0b88 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/77f59fb2d3aa33e90ec6cbbf45dcfb20ab82b1a9 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/9aff81e8217e9de2929084b03b3c7f81988c112b Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/b42821c15445f93daea3e76ada682b2b7181c476 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/b69933e97efea238ebbfcf70c2b1be1cd03f13e3 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/d4c6a6d08e70bb1083c7c405fc7faacbf19aebc0 Types: Patch

      Source identifier: nvd@nist.gov

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