CVE-2026-46124

Description

In the Linux kernel, the following vulnerability has been resolved: isofs: validate block number from NFS file handle in isofs_export_iget isofs_fh_to_dentry() and isofs_fh_to_parent() pass an attacker- controlled block number (ifid->block or ifid->parent_block) from the NFS file handle to isofs_export_iget(), which only rejects block == 0 before calling isofs_iget() and ultimately sb_bread(). A crafted file handle with fh_len sufficient to pass the check added by commit 0405d4b63d08 ("isofs: Prevent the use of too small fid") can still drive the server to read any in-range block on the backing device as if it were an iso_directory_record. That earlier fix was assigned CVE-2025-37780. sb_bread() on an out-of-range block returns NULL cleanly via the EIO path, so there is no memory-safety violation. For in-range reads of adjacent-partition data on the same block device, the unrelated bytes end up in iso_inode_info fields that reach the NFS client as dentry metadata. The deployment surface (isofs exported over NFS from loop-mounted images) is narrow and requires an authenticated NFS peer, but the malformed-file-handle class is reportable as hardening next to the existing CVE-2025-37780 fix. Reject block >= ISOFS_SB(sb)->s_nzones in isofs_export_iget() so the check covers both isofs_fh_to_dentry() and isofs_fh_to_parent() call sites with a single line.

Gravité et risque d'exploitation

CVE-2026-46124 obtient un score CVSS de 7.5/10, soit une gravité élevée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.48 %, ce qui la place devant 39.7 % des CVE référencées.

Que faire ?

• Vérifiez si Linux (versions <908a76f0b1038035e6ebb4f2293ce079f92e0a02, 56dfffea9fd3be0b3795a9ca6401e133a8427e0b, <=6.1.*, 7.0.7, <=6.12.*, 6.6.88, <=7.0.*, 63d5a3e207bf315a32c7d16de6c89753a759f95a, 0, <0a1af74ae2177bda3aee0837a0546309aa539d0d, <6.12.88, 5.10.237, <31dbb4ba0f719ae7774e4c0c95172c9bf81692f5, <ee0024f5a7e3c73aa253869fae9650ae054093ca, 6.12.88, 5.15.209, <=5.10.*, <=6.6.*, 6.1.175, <5.10.258, ee01a309ebf598be1ff8174901ed6e91619f1749, 6.1.135, 952e7a7e317f126d0a2b879fc531b716932d5ffa, 6.12.25, <24376458138387fb251e782e624c7776e9826796, <5.5, 7.1, <=6.18.*, 6.15, 5.10.258, 0405d4b63d082861f4eaff9d39c78ee9dc34f845, <6.6.140, <bb0988ed4f2e26d59bbb58f644cb3a55b7521e21, <=*, <5.15.209, <=5.15.*, 5.15.181, 5e7de55602c61c8ff28db075cc49c8dd6989d7e0, <afbafeddf23db13fe2edb2d5c0bf4bbb13d7881b, 6.14.4, <6.1.175, <6.15, 6.6.140, 6.18.30, 0fdafdaef796816a9ed0fd7ac812932d569d9beb, 5.4.293, <4c721a1d9b3c4fcaf59cc9b2281e3ec5a043e1a6, 007124c896e7d4614ac1f6bd4dedb975c35a2a8e) 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/ee0024f5a7e3c73aa253869fae9650ae054093ca
• https://git.kernel.org/stable/c/31dbb4ba0f719ae7774e4c0c95172c9bf81692f5
• https://git.kernel.org/stable/c/908a76f0b1038035e6ebb4f2293ce079f92e0a02
• https://git.kernel.org/stable/c/bb0988ed4f2e26d59bbb58f644cb3a55b7521e21
• https://git.kernel.org/stable/c/0a1af74ae2177bda3aee0837a0546309aa539d0d
• https://git.kernel.org/stable/c/afbafeddf23db13fe2edb2d5c0bf4bbb13d7881b
• https://git.kernel.org/stable/c/4c721a1d9b3c4fcaf59cc9b2281e3ec5a043e1a6
• https://git.kernel.org/stable/c/24376458138387fb251e782e624c7776e9826796