CVE-2026-23351

Description

In the Linux kernel, the following vulnerability has been resolved:netfilter: nft_set_pipapo: split gc into unlink and reclaim phaseYiming 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 userspacedumpers via the live copy of the data structure.call_rcu() does not protect us: dump operations or element lookups startingafter call_rcu has fired can still observe the freed element, unless thecommit phase has made enough progress to swap the clone and live pointersbefore any new reader has picked up the old version.This a similar approach as done recently for the rbtree backend in commit35f83a75529a (netfilter: nft_set_rbtree: dont gc elements on insert).

Risk Information

Associated Vulnerability

Patch Details

References

https://nvd.nist.gov/vuln/detail/CVE-2023-1234
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-1234