CVE-2026-52999

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nfnetlink_osf: fix out-of-bounds read on option matching In nf_osf_match(), the nf_osf_hdr_ctx structure is initialized once and passed by reference to nf_osf_match_one() for each fingerprint checked. During TCP option parsing, nf_osf_match_one() advances the shared ctx->optp pointer. If a fingerprint perfectly matches, the function returns early without restoring ctx->optp to its initial state. If the user has configured NF_OSF_LOGLEVEL_ALL, the loop continues to the next fingerprint. However, because ctx->optp was not restored, the next call to nf_osf_match_one() starts parsing from the end of the options buffer. This causes subsequent matches to read garbage data and fail immediately, making it impossible to log more than one match or logging incorrect matches. Instead of using a shared ctx->optp pointer, pass the context as a constant pointer and use a local pointer (optp) for TCP option traversal. This makes nf_osf_match_one() strictly stateless from the caller's perspective, ensuring every fingerprint check starts at the correct option offset.

Gravité et risque d'exploitation

CVE-2026-52999 obtient un score CVSS de 9.1/10, soit une gravité critique. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.59 %, ce qui la place devant 47.2 % des CVE référencées.

Que faire ?

• Vérifiez si Linux (versions <=6.1.*, <=7.0.*, <=6.12.*, <0145548346c4a30981a870a8ca00eac46ba27e85, <1c136f2c44a5913646bac85303612fd0825197a0, 0, <4.21, 6.18.33, 5.15.209, 1a6a0951fc009f6d9fe8ebea2d2417d80d54097b, <4.20, 6.12.91, <=5.10.*, <=6.6.*, 6.1.175, <21883587593d7c8bb519a79460a0b5bc5ffbdabd, 5.0, 6.6.141, <1e19a07291bb8682c14c39a64725a3ae54ab8ccc, <f5ca450087c3baf3651055e7a6de92600f827af3, <32e50f92c7cf3f4eba29622179a5fcdc2aebab41, 4.19.26, <5.0, <=6.18.*, 7.1, 7.0.10, 5.10.258, 0c1054e0e5fdef2369fb089e94def978bd209e1f, 4.20.13, <=*, <=5.15.*, 8316b60582facd4068fb0916c4db2418c21b7174, <edb78a142d2e5948e63647c0646aa7e7886935f0, <70a3f31d25cf2ec9d4ddfa408120171ead955623) 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/0145548346c4a30981a870a8ca00eac46ba27e85
• https://git.kernel.org/stable/c/1c136f2c44a5913646bac85303612fd0825197a0
• https://git.kernel.org/stable/c/1e19a07291bb8682c14c39a64725a3ae54ab8ccc
• https://git.kernel.org/stable/c/32e50f92c7cf3f4eba29622179a5fcdc2aebab41
• https://git.kernel.org/stable/c/70a3f31d25cf2ec9d4ddfa408120171ead955623
• https://git.kernel.org/stable/c/21883587593d7c8bb519a79460a0b5bc5ffbdabd
• https://git.kernel.org/stable/c/edb78a142d2e5948e63647c0646aa7e7886935f0
• https://git.kernel.org/stable/c/f5ca450087c3baf3651055e7a6de92600f827af3