CVE-2026-23351
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…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.13%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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").
- CVSS 3.1
- 7.8 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.13% probability · 2th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-416
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/16f3595c0441d87dfa005c47d8f95be213afaa9ePatch
- https://git.kernel.org/stable/c/500a50a301ce962b019ab95053ac70264fec2c21Patch
- https://git.kernel.org/stable/c/65ca51b9fb85477ab92a04295aed34b38f7c062ePatch
- https://git.kernel.org/stable/c/7864c667aed01a58b87ca518a631322cd0ac34c0Patch
- https://git.kernel.org/stable/c/9df95785d3d8302f7c066050117b04cd3c2048c2Patch
- https://git.kernel.org/stable/c/aff13667708dfa0dce136b8efd81baa9fa6ef261Patch
- https://git.kernel.org/stable/c/c0f1f85097ac2b6e7d750fe4d05807985cd3fd3aPatch
- https://git.kernel.org/stable/c/c12d570d71920903a1a0468b7d13b085203d0c93Patch
- https://cert-portal.siemens.com/productcert/html/ssa-019113.html
- https://cert-portal.siemens.com/productcert/html/ssa-082556.html
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.