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CVE-2026-74494

Vulnérabilité non évaluée dans Linux (Linux)

CVSS 0.0 · Non évaluée
EPSS 0.2%
Linux•Linux•Versions : <=6.1.*, <=6.12.*, 5.15.217, 0, <a60b5da05e318d9a364dbac38c347c7f24e625e7, <=7.1.*, <81e21cb7bd1479bb5238e0004a7e0110452c610b, <7e02cb30e8a1f5fc78cb10b220b06020e36d0bbe, <cb469993b3a61a72653770856d37af616d72d05f, <fd6a6c43f96b40a08a22ff62f08d194a49741c8a, <=6.6.*, <5.15, e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9, 5.15, <=6.18.*, 6.1.184, <0b1390cf2b6b91723b37c0909dd123f7a5eba1a7, <=*, <7fb8dbeb3f2868ae836ca12311d89aed16fc2927, <=5.15.*, 6.6.153, 7.1.8, 6.12.105, 6.18.44, 7.2

Description

In the Linux kernel, the following vulnerability has been resolved: ksmbd: reject repeated SMB2 NEGOTIATE requests Unauthenticated client can send multiple successful SMB2 NEGOTIATE requests on one connection before SESSION_SETUP. While the connection is in KSMBD_SESS_NEED_SETUP, smb2_handle_negotiate() accepts another SMB3.1.1 NEGOTIATE and overwrites conn->preauth_info with a new allocation. Only the final allocation is freed when the connection is released, leaking one object for every additional successful request. A repeated SMB2 NEGOTIATE after a dialect has been selected is a protocol violation. MS-SMB2 section 3.3.5.4 requires the server to disconnect without replying in this case. Set the connection exiting when rejecting the request, in addition to suppressing the response. Reject SMB2 NEGOTIATE unless the connection is new or is waiting for the SMB2 NEGOTIATE that follows an SMB1 multi-protocol negotiate. Serialize both SMB1 and SMB2 negotiation paths under conn->srv_mutex, since they update connection-wide dialect and negotiation state. Move the locking contract to ksmbd_smb_negotiate_common(), where the state and dialect are selected, and add ksmbd_conn_new() for consistent state access.

Gravité et risque d'exploitation

CVE-2026-74494 obtient un score CVSS de 0.0/10, soit une gravité non évaluée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.21 %, ce qui la place devant 11.1 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions <=6.1.*, <=6.12.*, 5.15.217, 0, <a60b5da05e318d9a364dbac38c347c7f24e625e7, <=7.1.*, <81e21cb7bd1479bb5238e0004a7e0110452c610b, <7e02cb30e8a1f5fc78cb10b220b06020e36d0bbe, <cb469993b3a61a72653770856d37af616d72d05f, <fd6a6c43f96b40a08a22ff62f08d194a49741c8a, <=6.6.*, <5.15, e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9, 5.15, <=6.18.*, 6.1.184, <0b1390cf2b6b91723b37c0909dd123f7a5eba1a7, <=*, <7fb8dbeb3f2868ae836ca12311d89aed16fc2927, <=5.15.*, 6.6.153, 7.1.8, 6.12.105, 6.18.44, 7.2) 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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