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CVE-2026-23436 Linux CVE debrief

The Linux kernel was vulnerable to a race condition in the shaper component, allowing for potential hierarchy leaks. The vulnerability has been resolved through patches. Affected users should apply patches to mitigate this vulnerability. The vulnerability has a CVSS score of 5.5 and a severity of MEDIUM. The vulnerability was resolved by taking the instance lock in pre-callbacks, preventing the netdev from being unregistered between ref taking and locking.

Vendor
Linux
Product
Unknown
CVSS
MEDIUM 5.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-04-03
Original CVE updated
2026-07-24
Advisory published
2026-04-03
Advisory updated
2026-07-24

Who should care

Users of Linux kernel versions 6.13.1 to 6.18.20, 6.19 to 6.19.10, and specific release candidates of version 7.0 should apply patches to mitigate this vulnerability. Linux kernel users and administrators should review and apply patches as recommended by the Linux kernel maintainers.

Technical summary

The Linux kernel's shaper component had a vulnerability that could lead to hierarchy leaks due to a race condition. This was resolved by taking the instance lock in pre-callbacks, preventing the netdev from being unregistered between ref taking and locking. Patches have been applied to affected versions, specifically for Linux kernel versions 6.13.1 to 6.18.20, 6.19 to 6.19.10. The vulnerability has a CVSS score of 5.5 and a severity of MEDIUM. Users of these versions should review and apply patches as recommended by the Linux kernel maintainers to mitigate this vulnerability. Evidence is limited to public sources and may not reflect the full scope or impact of the vulnerability. Defenders should verify affected systems and apply patches or mitigations as recommended.

Defensive priority

Medium priority due to CVSS score of 5.5 and availability impact.

Recommended defensive actions

  • Apply patches provided by the Linux kernel maintainers.
  • Inventory and update affected Linux kernel versions.
  • Monitor for potential exploitation attempts.
  • Review compensating controls for exposed systems while remediation is scheduled and verified.
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review.
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented.
  • Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.

Evidence notes

The CVE record was published on 2026-04-03T16:16:25.257Z and last modified on 2026-07-24T21:10:00.143Z. The NVD entry is currently Analyzed. Evidence is limited to public sources and may not reflect the full scope or impact of the vulnerability. Defenders should verify affected systems and apply patches or mitigations as recommended by the Linux kernel maintainers.

Official resources

AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-04-03T16:16:25.257Z and has not been modified since then. The NVD entry is currently Analyzed.