CVE-2026-23272

Summary

In the Linux kernel, the following vulnerability has been resolved:

netfilter: nf_tables: unconditionally bump set->nelems before insertion

In case that the set is full, a new element gets published then removed without waiting for the RCU grace period, while RCU reader can be walking over it already.

To address this issue, add the element transaction even if set is full, but toggle the set_full flag to report -ENFILE so the abort path safely unwinds the set to its previous state.

As for element updates, decrement set->nelems to restore it.

A simpler fix is to call synchronize_rcu() in the error path. However, with a large batch adding elements to already maxed-out set, this could cause noticeable slowdown of such batches.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux35d0ac9070ef619e3bf44324375878a1c540387b < 25fcaef7948912652905e96922f36583a84fffedaffected
LinuxLinux35d0ac9070ef619e3bf44324375878a1c540387b < e3ccb11fc8249759d23326038c8db987ddaabc77affected
LinuxLinux35d0ac9070ef619e3bf44324375878a1c540387b < 86bc4b1a0f672d47ac19f9022432cb6a2e01cb33affected
LinuxLinux35d0ac9070ef619e3bf44324375878a1c540387b < 6826131c7674329335ca25df2550163eb8a1fd0caffected
LinuxLinux35d0ac9070ef619e3bf44324375878a1c540387b < ccb8c8f3c1127cf34d18c737309897c68046bf21affected
LinuxLinux35d0ac9070ef619e3bf44324375878a1c540387b < def602e498a4f951da95c95b1b8ce8ae68aa733aaffected
LinuxLinuxfefdd79403e89b0c673965343b92e2e01e2713a8affected
LinuxLinux4.9.33 < 4.10affected
LinuxLinux4.10affected
LinuxLinux0 < 4.10unaffected
LinuxLinux6.1.177 <= 6.1.*unaffected
LinuxLinux6.6.141 <= 6.6.*unaffected
LinuxLinux6.12.91 <= 6.12.*unaffected
LinuxLinux6.18.17 <= 6.18.*unaffected
LinuxLinux6.19.7 <= 6.19.*unaffected
LinuxLinux7.0 <= *unaffected

Weaknesses

References