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PatchSiren cyber security CVE debrief

CVE-2026-31638 Linux CVE debrief

A Linux kernel vulnerability has been resolved in rxrpc, where a call reference was unconditionally dropped even if it was not acquired. This could lead to a kernel crash instead of properly rejecting a packet. The vulnerability affects Linux kernel versions and could lead to potential crashes if not properly patched. Linux kernel developers and administrators should verify kernel versions and apply patches to prevent potential issues. The patch fixes a protocol error path that could turn into a kernel crash.

Vendor
Linux
Product
Unknown
CVSS
HIGH 7.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-04-24
Original CVE updated
2026-10-19
Advisory published
2026-04-24
Advisory updated
2026-10-19

Who should care

Linux kernel developers and administrators responsible for maintaining Linux systems should verify kernel versions and apply patches to prevent potential issues. They should also review system logs for potential crashes or unusual activity. The vulnerability affects Linux kernel versions and could lead to potential crashes if not properly patched.

Why it matters

A Linux kernel vulnerability in rxrpc could lead to a kernel crash if not properly patched. Linux kernel developers and administrators should verify kernel versions and apply patches to prevent potential issues.

  • Verify Linux kernel versions to ensure patch application
  • Monitor system logs for potential crashes or unusual activity
  • Apply patches to prevent potential kernel crashes

Technical summary

The Linux kernel rxrpc implementation did not properly handle call references, leading to a potential kernel crash. A patch has been applied to fix this issue. The patch ensures that the call reference is only dropped if it was actually acquired, preventing a kernel crash. Linux kernel developers and administrators should verify kernel versions and apply patches to prevent potential issues. The vulnerability affects Linux kernel versions and could lead to potential crashes if not properly patched. The patch fixes a protocol error path that could turn into a kernel crash.

Defensive priority

Verify Linux kernel versions and apply patches to prevent potential crashes

Recommended defensive actions

  • Verify Linux kernel versions and apply patches
  • Review system logs for potential crashes
  • Monitor for unusual network activity
  • Perform vulnerability assessments
  • Implement compensating controls
  • Track exceptions and retest remediated assets
  • technicalSummary

Evidence notes

The CVE record and Linux kernel source code indicate a vulnerability in the rxrpc call reference handling. However, specific details about exploitation are limited. Defensive verification tasks include reviewing Linux kernel versions, monitoring system logs for potential crashes or unusual activity, and applying patches to prevent potential kernel crashes. Evidence limits are acknowledged, and further review is recommended.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-31638 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-31638

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

  • CVE-2026-31638 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-31638

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

Supplemental references

  • rxrpc: Only put the call ref if one was acquired

    Unverified legacy reference

    URL: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/31xxx/CVE-2026-31638.json

    cve_program_cvelist_v5

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/b8f66447448d6c305a51413a67ec8ed26aa7d1dd

    Supplemental source

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/0c156aff8a2d4fa0d61db7837641975cf0e5452d

    Supplemental source

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/8299ca146489664e3c0c90a3b8900d8335b1ede4

    Supplemental source

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/9fb09861e2b8d1abfe2efaf260c9f1d30080ea38

    Supplemental source

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/6331f1b24a3e85465f6454e003a3e6c22005a5c5

    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.