CVE-2026-43114

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nft_set_pipapo_avx2: don't return non-matching entry on expiry New test case fails unexpectedly when avx2 matching functions are used. The test first loads a ranomly generated pipapo set with 'ipv4 . port' key, i.e. nft -f foo. This works. Then, it reloads the set after a flush: (echo flush set t s; cat foo) | nft -f - This is expected to work, because its the same set after all and it was already loaded once. But with avx2, this fails: nft reports a clashing element. The reported clash is of following form: We successfully re-inserted a . b c . d Then we try to insert a . d avx2 finds the already existing a . d, which (due to 'flush set') is marked as invalid in the new generation. It skips the element and moves to next. Due to incorrect masking, the skip-step finds the next matching element *only considering the first field*, i.e. we return the already reinserted "a . b", even though the last field is different and the entry should not have been matched. No such error is reported for the generic c implementation (no avx2) or when the last field has to use the 'nft_pipapo_avx2_lookup_slow' fallback. Bisection points to 7711f4bb4b36 ("netfilter: nft_set_pipapo: fix range overlap detection") but that fix merely uncovers this bug. Before this commit, the wrong element is returned, but erronously reported as a full, identical duplicate. The root-cause is too early return in the avx2 match functions. When we process the last field, we should continue to process data until the entire input size has been consumed to make sure no stale bits remain in the map.

Gravité et risque d'exploitation

CVE-2026-43114 obtient un score CVSS de 9.4/10, soit une gravité critique. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.37 %, ce qui la place devant 29.4 % des CVE référencées.

Que faire ?

• Vérifiez si Linux (versions <=6.1.*, <=6.12.*, <fa4f1f52528c73989d820f32bfca06bec5afeece, 0, 6.12.83, 7.0, 7400b063969bdca4a06cd97f1294d765c8eecbe1, <d3c0037ffe1273fa1961e779ff6906234d6cf53c, <c7babe2f28b507e17f28e9f753b7caec72d4857f, <07de44424bb7f17ef9357e8535df96d9e97c40cb, 5.15.209, <5.7, <=5.10.*, <=6.6.*, 6.1.175, <=6.19.*, 6.6.136, <3d53f9aafd469ae1ea27051e00f5b96ca1b55d52, <1c43f0dd8691ddf8884793b481ddc7511cf593c3, <=6.18.*, 5.10.258, 5.7, <=*, 6.19.14, <0abbc43f71d99baadeeba6fa3fe1c80b676f57ed, <=5.15.*, 6.18.24, <f8c39983fc9c1a978c82e6f2df7bfba8a8561587) est présent sur votre parc.
• Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
• À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
• Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.

Références

• https://git.kernel.org/stable/c/f8c39983fc9c1a978c82e6f2df7bfba8a8561587
• https://git.kernel.org/stable/c/c7babe2f28b507e17f28e9f753b7caec72d4857f
• https://git.kernel.org/stable/c/1c43f0dd8691ddf8884793b481ddc7511cf593c3
• https://git.kernel.org/stable/c/fa4f1f52528c73989d820f32bfca06bec5afeece
• https://git.kernel.org/stable/c/3d53f9aafd469ae1ea27051e00f5b96ca1b55d52
• https://git.kernel.org/stable/c/07de44424bb7f17ef9357e8535df96d9e97c40cb
• https://git.kernel.org/stable/c/0abbc43f71d99baadeeba6fa3fe1c80b676f57ed
• https://git.kernel.org/stable/c/d3c0037ffe1273fa1961e779ff6906234d6cf53c