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CVE-2026-23351 Linux CVE debrief

A use-after-free vulnerability was found in the Linux kernel's netfilter: nft_set_pipapo. This vulnerability could lead to a local denial of service due to soft lockup warnings and RCU stall reports under a large number of expired elements. The issue arises from the garbage collection (GC) in the pipapo set type running for a long time in a non-preemptible context. To address this, the GC was split into an unlink and a reclaim phase, preventing the use-after-free vulnerability. Linux kernel users and administrators should be aware of this vulnerability and take necessary actions to protect their systems.

Vendor
Linux
Product
Unknown
CVSS
HIGH 7.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-03-25
Original CVE updated
2026-07-14
Advisory published
2026-03-25
Advisory updated
2026-07-14

Who should care

Linux kernel users and administrators should be aware of this vulnerability and take necessary actions to protect their systems. This includes inventorying Linux kernel versions, assessing vulnerability, applying patches or updates provided by Linux kernel maintainers, monitoring system logs for soft lockup warnings and RCU stall reports, and considering implementing compensating controls such as rate limiting or traffic shaping.

Technical summary

The vulnerability is caused by the garbage collection (GC) in the pipapo set type running for a long time in a non-preemptible context, leading to soft lockup warnings and RCU stall reports. To fix this issue, the GC was split into an unlink and a reclaim phase. This change ensures that elements are not queued for freeing until pointers have been swapped, preventing the use-after-free vulnerability. The fix modifies the netfilter: nft_set_pipapo to handle GC more efficiently.

Defensive priority

High

Recommended defensive actions

  • Inventory Linux kernel versions and assess vulnerability
  • Apply patches or updates provided by Linux kernel maintainers
  • Monitor system logs for soft lockup warnings and RCU stall reports
  • Consider implementing compensating controls, such as rate limiting or traffic shaping
  • Review and verify the affected scope and severity
  • Track exceptions and retest remediated assets
  • Plan vendor-supported updates or mitigations through normal change control

Evidence notes

The CVE record was published on 2026-03-25T11:16:33.450Z and was last modified on 2026-07-14T13:18:30.660Z. The NVD entry is currently Modified. This information is based on the provided source corpus. Further verification is recommended to ensure accuracy.

Official resources

AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-03-25T11:16:33.450Z and has not been modified since then.