MediumCVE-2026-98161

    Linux Kernel: Improper Check for Unusual or Exceptional Conditions (CVE-2026-98161)

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

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    What is affected, what to do

    In the Linux kernel, the following vulnerability has been resolved: nvdimm: pmem: keep PREFLUSH before data writes pmem_submit_bio() records a REQ_PREFLUSH error, but continues to copy the bio data and can later overwrite the error with a successful REQ_FUA flush. That lets data writes run after a failed preflush and can complete the bio successfully despite the failed ordering barrier.

    Update Linux Kernel to version 6.6.160, Linux Kernel to version 6.12.112, Linux Kernel to version 6.18.52.

    Affected
    • Linux Kernel lt 5.3..6.6.160
    • Linux Kernel lt 6.7..6.12.112
    • Linux Kernel lt 6.13..6.18.52
    • Linux Kernel lt 6.19..7.2.6
    Fixed in
    • Linux Kernel 6.6.160
    • Linux Kernel 6.12.112
    • Linux Kernel 6.18.52
    • Linux Kernel 7.2.6
    • Linux Kernel 7.3

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

    0.1 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 1.5

    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
    55.49 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
    1.5
    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
    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-754

    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: nvdimm: pmem: keep PREFLUSH before data writes pmem_submit_bio() records a REQ_PREFLUSH error, but continues to copy the bio data and can later overwrite the error with a successful REQ_FUA flush. That lets data writes run after a failed preflush and can complete the bio successfully despite the failed ordering barrier. Run the REQ_PREFLUSH flush synchronously before touching the bio data and complete the bio with the flush error if it fails. Keep asynchronous flush chaining for REQ_FUA. At that point, data copy has completed and the parent bio can wait for the chained flush bio.

    Source: Ubuntu Security Notices, Debian LTS Advisories, Debian Security Advisories, HKCERT (CC BY 3.0 HK) · HKCERT rating: medium, BSI WID Portal, BSI CSAF, NVD (NIST), 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
    • 6.19 – < 7.2.6
    • —
    • 6.13 – < 6.18.52
    • 5.3 – < 6.6.160
    • 6.7 – < 6.12.112
    • 7.2.6
    • 7.3
    • 6.18.52
    • 6.6.160
    • 6.12.112

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebianlinuxtrixie
    Linuxubuntulinuxresolute
    Linuxdebianlinux-6.12bookworm
    Linuxubuntulinux-awsresolute
    Linuxubuntulinux-gcpresolute
    Linuxubuntulinux-hwe-7.0noble
    Linuxubuntulinux-ibmresolute
    Linuxubuntulinux-oem-7.0resolute
    Linuxubuntulinux-oracleresolute
    Linuxlinuxlinux_kernel—

    Weakness classes (CWE)

    • CWE-754Improper Check for Unusual or Exceptional Conditions

      Class

      The product does not check or incorrectly checks for unusual or exceptional conditions that are not expected to occur frequently during day to day operation of the product.

      Entry at MITRE CWE-754

    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 2 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/2026/98xxx/CVE-2026-98161.json">CVE-2026-98161</a>
      Referenceadded
      —
      https://git.kernel.org/stable/c/22d1f4dcdc9c6d0295c6db0c8933126098b14e05

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

    2. Record modifiedLinux

      1 individual change: Affected versions (publisher)

      Show the original change
      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/2026/98xxx/CVE-2026-98161.json">CVE-2026-98161</a>

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

    3. Record modifiedLinux

      Show 2 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/2026/98xxx/CVE-2026-98161.json">CVE-2026-98161</a>
      Referenceadded
      —
      https://git.kernel.org/stable/c/d34c30bc994328d9cf6749b2e9a32aabd08fd076

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

    4. Initial analysis by NVDNVD

      Newly listed as affected:
      • Linux Kernel (6.19 – before 7.2.6; 5.3 – before 6.18.52)

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

      Weakness type: CWE-754

      Show 6 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      CVSSadded
      —
      AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
      Weakness type (CWE)added
      —
      CWE-754
      Product configurationadded
      —
      OR *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.19 up to (excluding) 7.2.6 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.3 up to (excluding) 6.18.52
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/72561ca1ab96f0f0f32737a6171641e05a318538 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/770a90c2127220f0fc194ce909ad4f0842e141cb Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/c644a2f8fef5618fcf453c591177700fd07dd024 Types: Patch

      Source identifier: nvd@nist.gov

    5. Record modifiedLinux

      1 individual change: Affected versions (publisher)

      Show the original change
      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/2026/98xxx/CVE-2026-98161.json">CVE-2026-98161</a>

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

    Show one older change

    1. ReceivedLinux

      Description added or changed

      Show 5 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Descriptionadded
      —
      In the Linux kernel, the following vulnerability has been resolved: nvdimm: pmem: keep PREFLUSH before data writes pmem_submit_bio() records a REQ_PREFLUSH error, but continues to copy the bio data and can later overwrite the error with a successful REQ_FUA flush. That lets data writes run after a failed preflush and can complete the bio successfully despite the failed ordering barrier. Run the REQ_PREFLUSH flush synchronously before touching the bio data and complete the bio with the flush error if it fails. Keep asynchronous flush chaining for REQ_FUA. At that point, data copy has completed and the parent bio can wait for the chained flush bio.
      Affected versions (publisher)added
      —
      New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/98xxx/CVE-2026-98161.json">CVE-2026-98161</a>
      Referenceadded
      —
      https://git.kernel.org/stable/c/72561ca1ab96f0f0f32737a6171641e05a318538
      Referenceadded
      —
      https://git.kernel.org/stable/c/770a90c2127220f0fc194ce909ad4f0842e141cb
      Referenceadded
      —
      https://git.kernel.org/stable/c/c644a2f8fef5618fcf453c591177700fd07dd024

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

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