CVE-2026-46303

Description

In the Linux kernel, the following vulnerability has been resolved: isofs: validate Rock Ridge CE continuation extent against volume size rock_continue() reads rs->cont_extent verbatim from the Rock Ridge CE record and passes it to sb_bread() without checking that the block number is within the mounted ISO 9660 volume. commit e595447e177b ("[PATCH] rock.c: handle corrupted directories") added cont_offset and cont_size rejection for the CE continuation but did not validate the extent block number itself. commit f54e18f1b831 ("isofs: Fix infinite looping over CE entries") later capped the CE chain length at RR_MAX_CE_ENTRIES = 32 but again left the block number unchecked. With a crafted ISO mounted via udisks2 (desktop optical auto-mount) or via CAP_SYS_ADMIN mount, rs->cont_extent can therefore point at an out-of-range block or at blocks belonging to an adjacent filesystem on the same block device. sb_bread() on an out-of-range block returns NULL cleanly via the block layer EIO path, so there is no memory-safety violation. For in-range reads of adjacent- filesystem data, the CE buffer is parsed as Rock Ridge records and only the text of SL sub-records reaches userspace through readlink(), which makes the info-leak channel narrow and difficult to exploit; still, rejecting the malformed CE outright matches the rejection shape already present in the same function for cont_offset and cont_size. Add an ISOFS_SB(sb)->s_nzones bounds check to rock_continue() next to the existing offset/size rejection, printing the same corrupted-directory-entry notice.

Gravité et risque d'exploitation

CVE-2026-46303 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 0.56 %, ce qui la place devant 45.8 % des CVE référencées.

Que faire ?

• Vérifiez si Linux (versions <22b36fa081f38ab397c7697f9d539211b51a0cfc, <=6.1.*, 7.0.7, <=7.0.*, <=6.12.*, <3.15, 3.17.8, <3.13, 3.19, <3.11, 0, <a36d990f591320e9dd379ab30063ebfe91d47e1f, 212c4d33ca83e2144064fe9c2911607fbed5386f, 96e44adce250199ec9b2b928be66365779ff1b59, 486aa789eadcf44ed87f972b209299c516454693, <3.3, f54e18f1b831c92f6512d2eedb224cd63d607d3d, <ef048470c90bc8c1b8318bb2ce329da9ef64b9fe, 6.12.88, b6d20edb6e7cedb4eedb9e0193d20dd488ebae84, 5.15.209, <=5.10.*, <=6.6.*, 6.1.175, <8356fb821016797f5677cbeee5ddc0d32a95b4be, 2.6.32.66, 3.10.64, <bf1bc673c587f5ef7e9c09b94aea7c5a7847d4d9, 3.2.67, <2.6.33, <c9b37c8b73f6368e4750e5ccb0632c380b43c6e5, <3.5, 7.1, <=6.18.*, 8190393a88f2b0321263a54f2a9eb5a2aa43be7e, 3.14.28, <3.18, 5.10.258, 3.4.107, <d582e12378bc1637f337622feef762f53c43fd57, <e69da8eeab74b4f4505024c38a17bce060fe7df8, <=*, 08313e26e06d4aa9ce1cbba1a8e359e9cab9ad56, 3.12.36, <=5.15.*, <3.19, 6.6.140, 3.18.2, 1fe5620fcd6c2f0a4a927ee10c8e53196da392f3, fbce0d7dc8965c9fb8d411862040239d4a768c71, 6.18.30) 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/8356fb821016797f5677cbeee5ddc0d32a95b4be
• https://git.kernel.org/stable/c/d582e12378bc1637f337622feef762f53c43fd57
• https://git.kernel.org/stable/c/bf1bc673c587f5ef7e9c09b94aea7c5a7847d4d9
• https://git.kernel.org/stable/c/c9b37c8b73f6368e4750e5ccb0632c380b43c6e5
• https://git.kernel.org/stable/c/22b36fa081f38ab397c7697f9d539211b51a0cfc
• https://git.kernel.org/stable/c/e69da8eeab74b4f4505024c38a17bce060fe7df8
• https://git.kernel.org/stable/c/ef048470c90bc8c1b8318bb2ce329da9ef64b9fe
• https://git.kernel.org/stable/c/a36d990f591320e9dd379ab30063ebfe91d47e1f