CriticalCVE-2026-53130

    Linux Kernel: security vulnerability (CVE-2026-53130)

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

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    What is affected, what to do

    In the Linux kernel, the following vulnerability has been resolved: fs/omfs: reject s_sys_blocksize smaller than OMFS_DIR_START omfs_fill_super() rejects oversized s_sys_blocksize values (> PAGE_SIZE), but it does not reject values smaller than OMFS_DIR_START (0x1b8 = 440). Later, omfs_make_empty() uses sbi->s_sys_blocksize - OMFS_DIR_START as the length argument to memset().

    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 2.6.27..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

    9.8

    Priority

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

    Source: NVD, CVSS v3

    7.8

    CVSS v3

    Severity High on the scale from 0 to 10.

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

    0.2 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 8.3

    Show all metrics
    Severity
    Critical
    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
    58.75 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
    9.8 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
    7.8
    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
    0.2 %
    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
    8.3
    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: fs/omfs: reject s_sys_blocksize smaller than OMFS_DIR_START omfs_fill_super() rejects oversized s_sys_blocksize values (> PAGE_SIZE), but it does not reject values smaller than OMFS_DIR_START (0x1b8 = 440). Later, omfs_make_empty() uses sbi->s_sys_blocksize - OMFS_DIR_START as the length argument to memset(). Since s_sys_blocksize is u32, a crafted filesystem image with s_sys_blocksize < OMFS_DIR_START causes an unsigned underflow there, wrapping to a value near 2^32. That drives a ~4 GiB memset() from bh->b_data + OMFS_DIR_START and overwrites kernel memory far beyond the backing block buffer. Add the corresponding lower-bound check alongside the existing upper-bound check in omfs_fill_super(), so that malformed images are rejected during superblock validation before any filesystem data is processed.

    Source: Debian LTS Advisories, BSI WID Portal, BSI CSAF, Ubuntu Security Notices, Microsoft Security Update Guide, 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 – < 6.1.175
    • 5.11 – < 5.15.209
    • 6.7 – < 6.12.91
    • —
    • 2.6.27 – < 5.10.258
    • 6.13 – < 6.18.33
    • 6.2 – < 6.6.141
    • 6.19 – < 7.0.10
    • 6.1.175
    • 5.15.209
    • 6.12.91
    • 7.1
    • 5.10.258
    • 6.18.33
    • 6.6.141
    • 7.0.10

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebianlinuxbookworm
    Linuxdebianlinuxbullseye
    Linuxdebianlinux-6.1bullseye
    Linuxubuntulinux-oracle-7.0noble
    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. Initial analysis by NVDNVD

      Newly listed as affected:
      • Linux Kernel (6.2 – before 6.6.141; 6.7 – before 6.12.91; 6.13 – before 6.18.33; 6.19 – before 7.0.10; 5.16 – before 6.1.175; 5.11 – before 5.15.209; 2.6.27 – before 5.10.258)

      Weakness type: CWE-191

      Show 10 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Weakness type (CWE)added
      —
      CWE-191
      Product configurationadded
      —
      OR *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.2 up to (excluding) 6.6.141 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.7 up to (excluding) 6.12.91 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.13 up to (excluding) 6.18.33 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.19 up to (excluding) 7.0.10 *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) 2.6.27 up to (excluding) 5.10.258
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/0621c385fda1376e967f37ccd534c26c3e511d14 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/131ea3e57fc22936ed0e2c8330f2e36106172f51 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/5822a05a841a10794ad818620dd2af490b0705d3 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/6561afc38398e3518a29c5eebb975c30468f98a6 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/754ff1bea3819a90c6f33cccfc1a299ef7609f07 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/79f84af38c9fef9deb0e02c79eb969b5541c2644 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/817f16ed62bc58a168417bfb5e859c2a370bab03 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/fbc72f5c645155dc2ed3573243ed20f9913e3a54 Types: Patch

      Source identifier: nvd@nist.gov

    2. ReceivedLinux

      Description added or changed

      Show 10 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      Linux, Linux
      Descriptionadded
      —
      In the Linux kernel, the following vulnerability has been resolved: fs/omfs: reject s_sys_blocksize smaller than OMFS_DIR_START omfs_fill_super() rejects oversized s_sys_blocksize values (> PAGE_SIZE), but it does not reject values smaller than OMFS_DIR_START (0x1b8 = 440). Later, omfs_make_empty() uses sbi->s_sys_blocksize - OMFS_DIR_START as the length argument to memset(). Since s_sys_blocksize is u32, a crafted filesystem image with s_sys_blocksize < OMFS_DIR_START causes an unsigned underflow there, wrapping to a value near 2^32. That drives a ~4 GiB memset() from bh->b_data + OMFS_DIR_START and overwrites kernel memory far beyond the backing block buffer. Add the corresponding lower-bound check alongside the existing upper-bound check in omfs_fill_super(), so that malformed images are rejected during superblock validation before any filesystem data is processed.
      Referenceadded
      —
      https://git.kernel.org/stable/c/0621c385fda1376e967f37ccd534c26c3e511d14
      Referenceadded
      —
      https://git.kernel.org/stable/c/131ea3e57fc22936ed0e2c8330f2e36106172f51
      Referenceadded
      —
      https://git.kernel.org/stable/c/5822a05a841a10794ad818620dd2af490b0705d3
      Referenceadded
      —
      https://git.kernel.org/stable/c/6561afc38398e3518a29c5eebb975c30468f98a6
      Referenceadded
      —
      https://git.kernel.org/stable/c/754ff1bea3819a90c6f33cccfc1a299ef7609f07
      Referenceadded
      —
      https://git.kernel.org/stable/c/79f84af38c9fef9deb0e02c79eb969b5541c2644
      Referenceadded
      —
      https://git.kernel.org/stable/c/817f16ed62bc58a168417bfb5e859c2a370bab03
      Referenceadded
      —
      https://git.kernel.org/stable/c/fbc72f5c645155dc2ed3573243ed20f9913e3a54

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

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