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PatchSiren cyber security CVE debrief

CVE-2026-80551 Linux CVE debrief

A vulnerability in the Linux kernel's s390/vfio_ccw subsystem has been addressed. The issue involves ensuring the first IDAW (Indirect Data Address Word) remains constant during reads to accurately calculate the buffer size needed for the IDAL (Indirect Data Address List). This vulnerability has been resolved with specific commits to the Linux kernel.

Vendor
Linux
Product
Unknown
CVSS
CRITICAL 9.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-08-26
Original CVE updated
2026-10-16
Advisory published
2026-08-26
Advisory updated
2026-10-16

Who should care

Defenders responsible for Linux kernel maintenance and systems utilizing the s390/vfio_ccw subsystem should assess exposure and apply patches as necessary. This includes operators, platform administrators, vulnerability management teams, and security teams who need to verify kernel versions, review system configurations, and monitor system logs for suspicious activity related to the s390/vfio_ccw subsystem.

Why it matters

This vulnerability in the Linux kernel's s390/vfio_ccw subsystem requires verification of kernel versions and patch application to prevent potential data corruption or system instability.

  • Verify patch application to prevent potential data corruption or system instability
  • Assess system configurations for exposure to the s390/vfio_ccw subsystem
  • Monitor system logs for suspicious activity related to the subsystem

Technical summary

The Linux kernel's s390/vfio_ccw subsystem has a vulnerability related to ensuring the first IDAW remains constant during reads. This issue has been addressed through specific commits to the Linux kernel. The vulnerability involves verifying that the address found in the first IDAW is unchanged between reads, to ensure a consistent set of IDAWs being worked with. Defenders should prioritize verifying the integrity of their Linux kernel versions and applying patches to address this vulnerability, particularly for systems utilizing the s390/vfio_ccw subsystem.

Defensive priority

Defenders should prioritize verifying the integrity of their Linux kernel versions and applying patches to address this vulnerability, particularly for systems utilizing the s390/vfio_ccw subsystem.

Recommended defensive actions

  • Verify Linux kernel versions for s390/vfio_ccw subsystem and apply patches as necessary
  • Review system configurations for potential exposure
  • Monitor system logs for suspicious activity related to the s390/vfio_ccw subsystem
  • Assess system configurations for exposure to the s390/vfio_ccw subsystem
  • Verify patch application to prevent potential data corruption or system instability
  • Review compensating controls for exposed systems while remediation is scheduled and verified
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The CVE record and associated source item provide details on the vulnerability, including its description and affected versions. However, specific exploit details or victim information are not provided.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-80551 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-80551

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-80551 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-80551

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • s390/vfio_ccw: Ensure first IDAW remains constant

    Unverified legacy reference

    URL: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/80xxx/CVE-2026-80551.json

    cve_program_cvelist_v5

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/460b977a4e71cc319fdadf91c193ec3beaa57263

    Supplemental source

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/0d46c2565f173bcddcdcaf44a4f69789a20535e2

    Supplemental source

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/08ef2a82115690d6e229615872ac1731af732497

    Supplemental source

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/fc59e9482117ebdccd6dc7fa8082f8b980fd021e

    Supplemental source

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/565bef268d75bf7df665bce6923a88cd0eb74592

    Supplemental source

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.