CVE-2026-23351 Details
Description
In the Linux kernel, the following vulnerability has been resolved: netfilter: nft_set_pipapo: split gc into unlink and reclaim phase Yiming Qian reports Use-after-free in the pipapo set type: Under a large number of expired elements, commit-time GC can run for a very long time in a non-preemptible context, triggering soft lockup warnings and RCU stall reports (local denial of service). We must split GC in an unlink and a reclaim phase. We cannot queue elements for freeing until pointers have been swapped. Expired elements are still exposed to both the packet path and userspace dumpers via the live copy of the data structure. call_rcu() does not protect us: dump operations or element lookups starting after call_rcu has fired can still observe the free'd element, unless the commit phase has made enough progress to swap the clone and live pointers before any new reader has picked up the old version. This a similar approach as done recently for the rbtree backend in commit 35f83a75529a ("netfilter: nft_set_rbtree: don't gc elements on insert").
A use-after-free vulnerability has been identified in the Linux kernel's netfilter component, specifically within the nft_set_pipapo set type. This issue arises when a large number of elements expire, causing the garbage collection (GC) process to run for an extended period in a non-preemptible context. This can trigger soft lockup warnings and RCU stall reports, leading to a local denial-of-service condition. The vulnerability allows expired elements to remain accessible via the live data structure copy, potentially causing inconsistencies during packet processing or when userspace dumpers access the data. The problem is exacerbated by the fact that the call_rcu() function does not provide adequate protection, as elements freed can still be observed by new readers unless the GC process has sufficiently progressed to update the pointers before the old version is accessed.
Users can upgrade to the patched version of the Linux kernel where this vulnerability has been addressed. The specific commit containing the fix is 16f3595c0441d87dfa005c47d8f95be213afaa9e.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
No SSVC data is available for this CVE.
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Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-416 | Use After Free | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| linux linux kernel | >= 5.6.1, < 5.10.253 >= 5.11, < 5.15.203 >= 5.16, < 6.1.167 >= 6.2, < 6.6.130 >= 6.7, < 6.12.77 >= 6.13, < 6.18.17 >= 6.19, < 6.19.7 5.6 - 7.0 rc1 7.0 rc2 7.0 rc3 7.0 rc4 7.0 rc5 7.0 rc6 7.0 rc7 |
CPE
Remediation
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Change History
6 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 14, 2026 | CVE Modified | siemens-SADP |
| Jun 17, 2026 | CVE Modified | kernel.org |
| Apr 24, 2026 | Initial Analysis | [email protected] |
| Apr 18, 2026 | CVE Modified | kernel.org |
| Apr 2, 2026 | CVE Modified | kernel.org |
| Mar 25, 2026 | New CVE Received | kernel.org |