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CVE-2026-89674

Vulnérabilité critique dans Linux (Linux)

CVSS 9.8 · Critique
EPSS 0.5%
Linux•Linux•Versions : <=6.1.*, <=6.12.*, 5.15.221, 5.10.270, 0, 7.2.4, <3a7fd224df0fbb42167eb1b77be45d72fe0b1098, 6.1.188, <=5.10.*, <=6.6.*, <f9868174af49d207fbaf0c5e055d088a983684af, 6.6.157, <c81cef6a805dec266c10fc4f83c93d6fcf1a2b43, <e7d9d23ecd9172f05b09bb678ff22db8e361c428, <65a72b721943618eeb3a41c8b36e915591f3f83f, <29e4478e2ed5a227e8f0c33cacb91bf227cedd47, <=6.18.*, <bee826c00ac900473f91306f1f3e5a5a81fd4a74, <=7.2.*, 4.8, <0380129b1373c437eb35401a174671c8888f4b80, <=*, <=5.15.*, <4.8, 6.18.50, 9b9960a0ca4773e21c4b153ed355583946346b25, 6.12.109, 7.3

Description

In the Linux kernel, the following vulnerability has been resolved: nfsd: fix XDR length calculation in nfsd4_ff_encode_layoutget The XDR buffer size calculation in nfsd4_ff_encode_layoutget() has multiple errors that can result in either an out-of-bounds write or leaking uninitialized kernel memory to the client: - fh_len doesn't account for XDR padding on the file handle data - uid and gid lengths use "8 + len" but xdr_encode_opaque() actually writes "4 + xdr_align_size(len)" bytes - ds_len omits the flags and stats_collect_hint fields (8 bytes), while len's header constant overestimates by 8 bytes -- these partially cancel but leave a net mismatch The worst case occurs with short strings (e.g. uid=0, gid=0 with an odd-sized file handle), where the function writes up to 5 bytes past the reserved XDR buffer. Conversely, when string lengths happen to be 4-byte aligned, the reservation is too large and stale buffer content is sent to the client. Fix this by breaking out every encoded field explicitly in the ds_len calculation, using xdr_align_size() for all variable-length opaque fields, and correcting the header constants.

Gravité et risque d'exploitation

CVE-2026-89674 obtient un score CVSS de 9.8/10, soit une gravité critique. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.51 %, ce qui la place devant 42.5 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions <=6.1.*, <=6.12.*, 5.15.221, 5.10.270, 0, 7.2.4, <3a7fd224df0fbb42167eb1b77be45d72fe0b1098, 6.1.188, <=5.10.*, <=6.6.*, <f9868174af49d207fbaf0c5e055d088a983684af, 6.6.157, <c81cef6a805dec266c10fc4f83c93d6fcf1a2b43, <e7d9d23ecd9172f05b09bb678ff22db8e361c428, <65a72b721943618eeb3a41c8b36e915591f3f83f, <29e4478e2ed5a227e8f0c33cacb91bf227cedd47, <=6.18.*, <bee826c00ac900473f91306f1f3e5a5a81fd4a74, <=7.2.*, 4.8, <0380129b1373c437eb35401a174671c8888f4b80, <=*, <=5.15.*, <4.8, 6.18.50, 9b9960a0ca4773e21c4b153ed355583946346b25, 6.12.109, 7.3) 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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