CVE-2026-64533

Description

In the Linux kernel, the following vulnerability has been resolved: fs/ntfs3: validate lcns_follow in log_replay conversion log_replay() converts DIR_PAGE_ENTRY_32 records into DIR_PAGE_ENTRY records when replaying version 0 restart tables. During this conversion, the memmove() length is derived directly from the on-disk lcns_follow field: memmove(&dp->vcn, &dp0->vcn_low, 2 * sizeof(u64) + le32_to_cpu(dp->lcns_follow) * sizeof(u64)); check_rstbl() validates restart table structure, but does not constrain per-entry lcns_follow values relative to the entry size. A malformed filesystem image can provide an oversized lcns_follow value, causing the conversion memmove() to access memory beyond the bounds of the allocated restart table buffer. The same field is later used to bound iteration over page_lcns[], so validating lcns_follow during conversion also prevents downstream out-of-bounds access from the same malformed metadata. Compute the maximum valid lcns_follow from the already-validated restart table entry size and reject entries that exceed this bound. Reuse the existing t16/t32 scratch variables already declared in log_replay() to avoid introducing new declarations. [almaz.alexandrovich@paragon-software.com: fixed the conflicts]

Gravité et risque d'exploitation

CVE-2026-64533 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 0.14 %, ce qui la place devant 2.6 % des CVE référencées.

Que faire ?

• Vérifiez si Linux (versions <32b9f8733feb241627fa5f564b1a99b5cae974c5, <=6.1.*, 7.1.5, 6.18.40, <=6.12.*, b46acd6a6a627d876898e1c84d3f84902264b445, <57c071e2c4f30b9c6f5aacb6679aab1269fbae99, 0, <7adb38279812c9c06b0e3fa7382f4d7887f3fa2d, <=7.1.*, <159f694d682e4215b3822ae31ed3a4631628fe55, 6.1.178, 6.12.97, <=6.6.*, <5.15, 5.15, <=6.18.*, 5.15.212, 6.6.145, <6a4c53a2e26a865565bd6a460961e8d6fcb32329, <ca343a99806b4fc8e27c48f08be3445c5fcd1445, <ddfc8683e1a627dbf1b83bacf8961443dd654258, <=*, <=5.15.*, 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

• https://git.kernel.org/stable/c/ca343a99806b4fc8e27c48f08be3445c5fcd1445
• https://git.kernel.org/stable/c/ddfc8683e1a627dbf1b83bacf8961443dd654258
• https://git.kernel.org/stable/c/57c071e2c4f30b9c6f5aacb6679aab1269fbae99
• https://git.kernel.org/stable/c/159f694d682e4215b3822ae31ed3a4631628fe55
• https://git.kernel.org/stable/c/7adb38279812c9c06b0e3fa7382f4d7887f3fa2d
• https://git.kernel.org/stable/c/32b9f8733feb241627fa5f564b1a99b5cae974c5
• https://git.kernel.org/stable/c/6a4c53a2e26a865565bd6a460961e8d6fcb32329