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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
2026-07-14
Original CVE updated
2026-07-28
Advisory published
2026-07-14
Advisory updated
2026-07-28

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.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-23351 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-23351

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

  • CVE-2026-23351 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-23351

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

Supplemental references

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/16f3595c0441d87dfa005c47d8f95be213afaa9e

    416baaa9-dc9f-4396-8d5f-8c081fb06d67 - Patch

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/500a50a301ce962b019ab95053ac70264fec2c21

    416baaa9-dc9f-4396-8d5f-8c081fb06d67 - Patch

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/65ca51b9fb85477ab92a04295aed34b38f7c062e

    416baaa9-dc9f-4396-8d5f-8c081fb06d67 - Patch

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/7864c667aed01a58b87ca518a631322cd0ac34c0

    416baaa9-dc9f-4396-8d5f-8c081fb06d67 - Patch

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/9df95785d3d8302f7c066050117b04cd3c2048c2

    416baaa9-dc9f-4396-8d5f-8c081fb06d67 - Patch

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/aff13667708dfa0dce136b8efd81baa9fa6ef261

    416baaa9-dc9f-4396-8d5f-8c081fb06d67 - Patch

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/c0f1f85097ac2b6e7d750fe4d05807985cd3fd3a

    416baaa9-dc9f-4396-8d5f-8c081fb06d67 - Patch

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.