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CVE-2026-64578

Vulnérabilité élevée dans Linux (Linux)

CVSS 8.2 · Élevée
EPSS 0.3%
Linux•Linux•Versions : <=6.1.*, <=6.12.*, <15b38176fd1530372905c602fde51fe89ec8c877, <f0e337e7db67cc1c832958bbb6c4026bdceacfdb, 6.12.101, <2c307126ed8e7adddab82b8e31d962d3a2156ab1, 0, <f7550a91ab211726f59cb137523b7a9eae1ac6eb, <=7.1.*, 5.15.216, <=6.6.*, <5.15, 6.18.42, e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9, <415d0fff0451ad7ad4caa910f2bb0f562f0fd60f, 7.1.6, 6.1.183, 5.15, <=6.18.*, <ea128f06d2fb2186f0cac0c9f3e953e4d1f5c29a, <=*, <=5.15.*, <1b6740525f5af90868d557c31b496ae689c8c549, 6.6.148, 7.2

Description

In the Linux kernel, the following vulnerability has been resolved: ksmbd: validate compound request size before reading StructureSize2 When ksmbd validates a compound (chained) SMB2 request, ksmbd_smb2_check_message() reads pdu->StructureSize2 without first checking that the compound element is large enough to contain it. StructureSize2 is a 2-byte field at offset 64 (__SMB2_HEADER_STRUCTURE_SIZE) from the start of each element. The compound-walking logic only guarantees that a full 64-byte SMB2 header is present for the trailing element: when NextCommand is 0, len is reduced to the number of bytes remaining after next_smb2_rcv_hdr_off. A remote client can craft a compound request whose last element has exactly 64 bytes, so the 2-byte StructureSize2 read at offset 64 extends one byte past the receive buffer, producing a slab-out-of-bounds read. BUG: KASAN: slab-out-of-bounds in ksmbd_smb2_check_message (fs/smb/server/smb2misc.c:402) Read of size 2 at addr ffff888012ae31ac by task kworker/0:1/14 The buggy address is located 172 bytes inside of allocated 173-byte region Workqueue: ksmbd-io handle_ksmbd_work Call Trace: ... kasan_report (mm/kasan/report.c:595) ksmbd_smb2_check_message (fs/smb/server/smb2misc.c:402) handle_ksmbd_work (fs/smb/server/server.c:119) process_one_work (kernel/workqueue.c:3314) worker_thread (kernel/workqueue.c:3397) kthread (kernel/kthread.c:436) ret_from_fork (arch/x86/kernel/process.c:158) ret_from_fork_asm (arch/x86/entry/entry_64.S:245) Reject any compound element that is too small to hold StructureSize2 before dereferencing it.

Gravité et risque d'exploitation

CVE-2026-64578 obtient un score CVSS de 8.2/10, soit une gravité élevée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.34 %, ce qui la place devant 25.5 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions <=6.1.*, <=6.12.*, <15b38176fd1530372905c602fde51fe89ec8c877, <f0e337e7db67cc1c832958bbb6c4026bdceacfdb, 6.12.101, <2c307126ed8e7adddab82b8e31d962d3a2156ab1, 0, <f7550a91ab211726f59cb137523b7a9eae1ac6eb, <=7.1.*, 5.15.216, <=6.6.*, <5.15, 6.18.42, e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9, <415d0fff0451ad7ad4caa910f2bb0f562f0fd60f, 7.1.6, 6.1.183, 5.15, <=6.18.*, <ea128f06d2fb2186f0cac0c9f3e953e4d1f5c29a, <=*, <=5.15.*, <1b6740525f5af90868d557c31b496ae689c8c549, 6.6.148, 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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