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CVE-2026-31516 Linux CVE debrief

A Linux kernel vulnerability, CVE-2026-31516, allows a race condition between policy_hthresh.work and netns teardown, potentially leading to stale memory access. This issue is resolved in later kernel versions. Linux administrators and developers should assess exposure and apply kernel updates to prevent potential stale memory access. The vulnerability is related to the xfrm subsystem and requires synchronization of policy_hthresh.work in xfrm_policy_fini() to prevent the race condition.

Vendor
Linux
Product
Unknown
CVSS
HIGH 7.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-04-22
Original CVE updated
2026-10-19
Advisory published
2026-04-22
Advisory updated
2026-10-19

Who should care

Linux administrators and developers should assess exposure and apply kernel updates to prevent potential stale memory access. The vulnerability affects Linux kernel deployments, and operators, platform, vulnerability-management, and security teams should review system configurations and apply updates to address the vulnerability.

Why it matters

CVE-2026-31516 is a Linux kernel vulnerability that allows a race condition between policy_hthresh.work and netns teardown, potentially leading to stale memory access. Linux administrators and developers should assess exposure and apply kernel updates to prevent potential issues.

  • Verify kernel versions and apply updates to address the vulnerability
  • Monitor system logs for potential issues related to the vulnerability
  • Review system configurations for exposure to the vulnerability

Technical summary

The Linux kernel vulnerability CVE-2026-31516 allows a race condition between policy_hthresh.work and netns teardown. This issue can lead to stale memory access if the net namespace is torn down before the work runs. The vulnerability is resolved by synchronizing policy_hthresh.work in xfrm_policy_fini(). The issue is related to the xfrm subsystem and requires synchronization to prevent the race condition. Linux administrators and developers should assess exposure and apply kernel updates to prevent potential stale memory access.

Defensive priority

Apply kernel updates to prevent potential stale memory access

Recommended defensive actions

  • Apply kernel updates to address the vulnerability
  • Review system configurations for exposure
  • Monitor system logs for potential issues
  • Verify kernel versions and apply updates to address the vulnerability
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented.
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review.
  • Review compensating controls for exposed systems while remediation is scheduled and verified.

Evidence notes

The CVE record and source item provide details on the vulnerability, while kernel.org references offer patch information. The vulnerability has been resolved in later kernel versions, and Linux administrators and developers should assess exposure and apply kernel updates. The issue is related to the xfrm subsystem and requires synchronization of policy_hthresh.work in xfrm_policy_fini().

Sources and references

Verified primary and authoritative sources

  • CVE-2026-31516 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-31516

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

  • CVE-2026-31516 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-31516

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

Supplemental references

  • xfrm: prevent policy_hthresh.work from racing with netns teardown

    Unverified legacy reference

    URL: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/31xxx/CVE-2026-31516.json

    cve_program_cvelist_v5

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/56ea2257b83ee29a543f158159e3d1abc1e3e4fe

    Supplemental source

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/8854e9367465d784046362698731c1111e3b39b8

    Supplemental source

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/4e2e77843fef473ef47e322d52436d8308582a96

    Supplemental source

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/29fe3a61bcdce398ee3955101c39f89c01a8a77e

    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.