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CVE-2026-64531

Vulnérabilité élevée dans Linux (Linux)

CVSS 7.8 · Élevée
EPSS 0.4%
Linux•Linux•Versions : <3f1f755366687d051174739fb99f7d560202f60b, <=6.1.*, 6.18.40, <=6.12.*, 7.1.5, <dbd14f736be02cfe73049bd801af89becd1a0749, 5.15.180, <5.15.212, a1e64addf3ff9257b45b78bc7d743781c3f41340, 057dbc5b72e9fcac439cd561c3a539b8a0edeb92, 0, <d573250d228401f707f4dbc09d11227a6215ee5f, <1b41cbe05b184f8861712f0806cc0c4f5d8c6dfe, <=7.1.*, 6.12.20, <f1efff8858403191361a01269c6fe8dd7f55a385, 6.14, 6.1.178, 6.12.97, <=6.6.*, <6.1.178, 6.13.8, 6.1.132, 2532adbfe917c0e71dba2650ffc6efe396314c87, e6610f9c08b4c04cf7949c10fc246c071d00e935, <=6.18.*, 5.15.212, 6.6.145, <6.6.145, <=*, <c66bd2626c2764f23764ff0f8277f44a9cfe8349, 6.6.84, <=5.15.*, 4b1a0ee6164c7204c68ab5a9c48c07bfe8852485, <6.14, <6.12.97, 6b099d285d7ed324494b6d684f377aa103856118, 7.2, <ab855641241387db062a5e41d9ad6b8561542572

Description

In the Linux kernel, the following vulnerability has been resolved: net: openvswitch: reject oversized nested action attrs Open vSwitch stores generated flow actions as nlattrs, whose nla_len field is u16. Commit a1e64addf3ff ("net: openvswitch: remove misbehaving actions length check") allowed the total sw_flow_actions stream to grow beyond 64 KiB, which is valid, but also removed the last guard preventing a generated nested action attribute from exceeding U16_MAX. An oversized generated container can thus be closed with a truncated nla_len. A later dump or teardown then walks a structurally different stream than the one that was validated. In particular, an oversized nested CLONE/CT action may cause subsequent bytes in the generated stream to be interpreted as independent actions. Keep the larger total-action-stream behavior, but make nested action close reject generated containers that do not fit in nla_len, and return the error through all callers. For recursive SAMPLE, CLONE, DEC_TTL, and CHECK_PKT_LEN builders, trim resource-owning action-list tails in reverse construction order before discarding failed wrappers, so resources copied into the rejected tails are released before the wrappers are removed. Most failed outer wrappers are discarded by truncating actions_len after child resources have been released. CHECK_PKT_LEN also trims its parent after branch resources are gone. SET/TUNNEL close failures unwind their known tun_dst ownership directly, and SET_TO_MASKED has no external ownership and truncates on close failure.

Gravité et risque d'exploitation

CVE-2026-64531 obtient un score CVSS de 7.8/10, soit une gravité élevée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.38 %, ce qui la place devant 30.5 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions <3f1f755366687d051174739fb99f7d560202f60b, <=6.1.*, 6.18.40, <=6.12.*, 7.1.5, <dbd14f736be02cfe73049bd801af89becd1a0749, 5.15.180, <5.15.212, a1e64addf3ff9257b45b78bc7d743781c3f41340, 057dbc5b72e9fcac439cd561c3a539b8a0edeb92, 0, <d573250d228401f707f4dbc09d11227a6215ee5f, <1b41cbe05b184f8861712f0806cc0c4f5d8c6dfe, <=7.1.*, 6.12.20, <f1efff8858403191361a01269c6fe8dd7f55a385, 6.14, 6.1.178, 6.12.97, <=6.6.*, <6.1.178, 6.13.8, 6.1.132, 2532adbfe917c0e71dba2650ffc6efe396314c87, e6610f9c08b4c04cf7949c10fc246c071d00e935, <=6.18.*, 5.15.212, 6.6.145, <6.6.145, <=*, <c66bd2626c2764f23764ff0f8277f44a9cfe8349, 6.6.84, <=5.15.*, 4b1a0ee6164c7204c68ab5a9c48c07bfe8852485, <6.14, <6.12.97, 6b099d285d7ed324494b6d684f377aa103856118, 7.2, <ab855641241387db062a5e41d9ad6b8561542572) 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

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