HighCVE-2026-98626

    Linux Kernel: security vulnerability (CVE-2026-98626)

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

    What is affected, what to do

    In the Linux kernel, the following vulnerability has been resolved: bpf: Restrict CO-RE poisoning to relocatable instructions CO-RE relocation records can name any instruction offset. When a relocation cannot be resolved, bpf_core_patch_insn() currently poisons its target before checking whether that instruction is a valid relocation target.

    Update Linux Kernel to version 5.15.222, Linux Kernel to version 6.1.189, Linux Kernel to version 6.6.158.

    Affected
    • Linux Kernel lt 5.6..5.15.222
    • Linux Kernel lt 5.16..6.1.189
    • Linux Kernel lt 6.2..6.6.158
    • Linux Kernel lt 6.7..6.12.112
    • Linux Kernel lt 6.13..6.18.55
    • Linux Kernel lt 6.19..7.2.9
    Fixed in
    • Linux Kernel 5.15.222
    • Linux Kernel 6.1.189
    • Linux Kernel 6.6.158
    • Linux Kernel 6.12.112
    • Linux Kernel 6.18.55
    • Linux Kernel 7.2.9
    • Linux Kernel 7.3

    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: Vendor (CNA), CVSS v3

    7.1

    CVSS v3

    Severity High on the scale from 0 to 10.

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

    0.2 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 11.6

    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
    66.57 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
    0.2 %
    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
    11.6
    Elevated — this CVE ranks above at least 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: bpf: Restrict CO-RE poisoning to relocatable instructions CO-RE relocation records can name any instruction offset. When a relocation cannot be resolved, bpf_core_patch_insn() currently poisons its target before checking whether that instruction is a valid relocation target. Malformed metadata can therefore replace jumps, calls, exits, register-source arithmetic, or non-immediate loads instead of failing at the relocation step. Handle poisoning only after the instruction has passed the same class and operand-form checks used for a resolved relocation. Route invalid forms through the existing diagnostic and return a hard error. Keep poisoning supported instructions, including both halves of a plain ldimm64, so an unresolved relocation in dead code remains valid. Extend bpf_core_poison_insn() to poison both halves of ldimm64, and return its status directly from each validated instruction case. This avoids routing the success path through a common label and leaves the helper free to report errors. The shared relocation code applies this restriction to both libbpf and in-kernel CO-RE.

    Source: Debian LTS Advisories, Microsoft Security Update Guide, cvelistv5, NVD (NIST), BSI WID Portal, BSI CSAF

    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 – < 6.1.189
    • 6.13 – < 6.18.55
    • 6.2 – < 6.6.158
    • —
    • 6.7 – < 6.12.112
    • 6.19 – < 7.2.9
    • 5.6 – < 5.15.222
    • 6.1.189
    • 6.18.55
    • 6.6.158
    • 7.3
    • 6.12.112
    • 7.2.9
    • 5.15.222

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebianlinux-6.12bookworm

    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

      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-2026-98626.json">CVE-2026-98626</a>

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

    2. ReceivedLinux

      Description added or changed

      Show 9 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Descriptionadded
      —
      In the Linux kernel, the following vulnerability has been resolved: bpf: Restrict CO-RE poisoning to relocatable instructions CO-RE relocation records can name any instruction offset. When a relocation cannot be resolved, bpf_core_patch_insn() currently poisons its target before checking whether that instruction is a valid relocation target. Malformed metadata can therefore replace jumps, calls, exits, register-source arithmetic, or non-immediate loads instead of failing at the relocation step. Handle poisoning only after the instruction has passed the same class and operand-form checks used for a resolved relocation. Route invalid forms through the existing diagnostic and return a hard error. Keep poisoning supported instructions, including both halves of a plain ldimm64, so an unresolved relocation in dead code remains valid. Extend bpf_core_poison_insn() to poison both halves of ldimm64, and return its status directly from each validated instruction case. This avoids routing the success path through a common label and leaves the helper free to report errors. The shared relocation code applies this restriction to both libbpf and in-kernel CO-RE.
      Affected versions (publisher)added
      —
      New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/98xxx/CVE-2026-98626.json">CVE-2026-98626</a>
      Referenceadded
      —
      https://git.kernel.org/stable/c/2d7d04357c41aa49a5ac658fcc207439f2ad6456
      Referenceadded
      —
      https://git.kernel.org/stable/c/394ae398337c5f87e567f6cd63b937fc2b2f6ddc
      Referenceadded
      —
      https://git.kernel.org/stable/c/8e4cbcca1e0a2fc5e6c8edb68e0cf5f2587f9319
      Referenceadded
      —
      https://git.kernel.org/stable/c/a0b79cdfcf34b53c85bac2d3cf022fc1342eeca0
      Referenceadded
      —
      https://git.kernel.org/stable/c/a8c47e62d9aea2d47a09e06c1682c59c21b92449
      Referenceadded
      —
      https://git.kernel.org/stable/c/d3219c229d16900cef936adad28633c98946e432
      Referenceadded
      —
      https://git.kernel.org/stable/c/f2a24101e89dd0804e717da7c1bd6af513698aa2

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

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