Linux Kernel nf_tables RCU Read/Write Crash Vulnerability
CVE-2026-23272 Published on March 20, 2026
netfilter: nf_tables: unconditionally bump set->nelems before insertion
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.
Products Associated with CVE-2026-23272
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Affected Versions
Linux:- Version 35d0ac9070ef619e3bf44324375878a1c540387b and below 6826131c7674329335ca25df2550163eb8a1fd0c is affected.
- Version 35d0ac9070ef619e3bf44324375878a1c540387b and below ccb8c8f3c1127cf34d18c737309897c68046bf21 is affected.
- Version 35d0ac9070ef619e3bf44324375878a1c540387b and below def602e498a4f951da95c95b1b8ce8ae68aa733a is affected.
- Version fefdd79403e89b0c673965343b92e2e01e2713a8 is affected.
- Version 4.10 is affected.
- Before 4.10 is unaffected.
- Version 6.18.17, <= 6.18.* is unaffected.
- Version 6.19.7, <= 6.19.* is unaffected.
- Version 7.0-rc3, <= * is unaffected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.