netfilter: nf_tables: unconditionally bump set->nelems before insertion
The Linux kernel nf_tables code is affected from 4.10 until fixed in stable releases 6.1.177, 6.6.141, 6.12.91, 6.18.17 or 6.19.7, depending on branch. CVSS rates it 7.8, high.
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Specific setups only
- Fix
- Fixed in 4.10, 6.1.177, 6.6.141, 6.12.91, 6.18.17, and 1 more
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: no
- Technical impact: total
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.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: total
- Record last updated
Affected versions
- Linux Linux
From 4.9.33 · fixed in 4.10
- Linux Linux
4.10
- KernelLinux
From 4.10.0 · fixed in 6.1.177; From 6.2.0 · fixed in 6.6.141; From 6.7.0 · fixed in 6.12.91; From 6.13.0 · fixed in 6.18.17; From 6.19.0 · fixed in 6.19.7
References 8
git.kernel.org
- stable/c/25841e8d4241c6c3763e70ae95050f8108707b46
- stable/c/022effa9c54903858e443b1225370e6c758d03f6
- stable/c/25fcaef7948912652905e96922f36583a84fffed
- stable/c/e3ccb11fc8249759d23326038c8db987ddaabc77
- stable/c/86bc4b1a0f672d47ac19f9022432cb6a2e01cb33
- stable/c/6826131c7674329335ca25df2550163eb8a1fd0c
- stable/c/ccb8c8f3c1127cf34d18c737309897c68046bf21
- stable/c/def602e498a4f951da95c95b1b8ce8ae68aa733a
Questions about CVE-2026-23272
What does this mean?
In the nf_tables netfilter code, a set's element counter is increased before insertion regardless of conditions. When the set is full, a new element still gets published.Source: git.kernel.org
Am I affected, and how do I check?
Affected kernels run from 4.10 up to the fixed stable release on each branch: 6.1.177, 6.6.141, 6.12.91, 6.18.17 and 6.19.7. Check the kernel version with uname -r and whether nftables sets are in use with nft list ruleset.Source: git.kernel.org
What should I do about it?
Update to the fixed stable release for the branch in use: 6.1.177, 6.6.141, 6.12.91, 6.18.17 or 6.19.7, or a later release on that branch.Source: git.kernel.org
Is it being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data