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CVE-2026-89490

Vulnérabilité non évaluée dans Linux (Linux)

CVSS 0.0 · Non évaluée
EPSS 0.2%
Linux•Linux•Versions : <=6.1.*, <=6.12.*, 5.15.221, 5.10.270, 0, 7.2.4, 6.1.188, <f9dd5cad8d09110ddff2db1fe756aae93c7552ff, <a63308ab426f3a3c7e33b02c150ea59054620261, <=5.10.*, <=6.6.*, 6.6.157, <1ae7029823ae4c91664cb32eec7fb8dd5e1a337a, 2.6.16, ccd979bdbce9fba8412beb3f1de68a9d0171b12c, <=6.18.*, <c0c165487a2ea5a37ddcdab4259157b7a527129c, 7.3, <=7.2.*, <=*, <b53e2b271eeb6040c2a4a78230c570dc41cdcfa4, <c28dc3407937aa8f225942538cd585c9b28ea65a, <=5.15.*, <1001fb3b69a11eaa0dc7c7428f6edfa48b88997a, 6.18.50, <2.6.16, 6.12.109, <94569154ba49f5f85645d2019c8e206213d8404e

Description

In the Linux kernel, the following vulnerability has been resolved: ocfs2: fix readdir position truncation on 32-bit kernels In ocfs2_dir_foreach_blk_el(), the directory cookie position is rebuilt with ctx->pos = (ctx->pos & ~(sb->s_blocksize - 1)) | offset; `ctx->pos` is loff_t (signed 64-bit), while `sb->s_blocksize` is unsigned long. On 32-bit kernels unsigned long is 32-bit, so the mask ~(sb->s_blocksize - 1) is computed as a 32-bit unsigned value (e.g. 0xfffff000 for a 4 KiB block size). In the AND expression with the 64-bit `ctx->pos`, that unsigned operand is zero-extended to 64 bits per the usual arithmetic conversions, yielding 0x00000000fffff000. The high 32 bits of `ctx->pos` are silently cleared, even though directory size is allowed to exceed 4 GiB. When readdir() crosses the 4 GiB boundary on a 32-bit kernel the position is reset back into the first 4 GiB block, making the re-validation path re-enumerate already-returned dirents indefinitely. This is ocfs2_dir_foreach_blk_el(), the extent-list readdir path taken for all non-inline directories, so a directory large enough to cross 4 GiB reaches it. This is the same class of bug that commit 3dce5bb82c97 ("exfat: Fix bitwise operation having different size") fixed in exfat, and the fix mirrors the equivalent ext4 fix in this series. Cast the operand to loff_t so the mask is 64-bit before the AND: ctx->pos = (ctx->pos & ~((loff_t)sb->s_blocksize - 1)) | offset; 64-bit kernels are unaffected.

Gravité et risque d'exploitation

CVE-2026-89490 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 0.18 %, ce qui la place devant 6.8 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions <=6.1.*, <=6.12.*, 5.15.221, 5.10.270, 0, 7.2.4, 6.1.188, <f9dd5cad8d09110ddff2db1fe756aae93c7552ff, <a63308ab426f3a3c7e33b02c150ea59054620261, <=5.10.*, <=6.6.*, 6.6.157, <1ae7029823ae4c91664cb32eec7fb8dd5e1a337a, 2.6.16, ccd979bdbce9fba8412beb3f1de68a9d0171b12c, <=6.18.*, <c0c165487a2ea5a37ddcdab4259157b7a527129c, 7.3, <=7.2.*, <=*, <b53e2b271eeb6040c2a4a78230c570dc41cdcfa4, <c28dc3407937aa8f225942538cd585c9b28ea65a, <=5.15.*, <1001fb3b69a11eaa0dc7c7428f6edfa48b88997a, 6.18.50, <2.6.16, 6.12.109, <94569154ba49f5f85645d2019c8e206213d8404e) 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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