CVE-2026-72427

Description

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix effective prog array index with BPF_F_PREORDER replace_effective_prog() and purge_effective_progs() located the slot in the effective array by walking the program hlist and counting entries linearly. That count does not match the array layout: compute_effective_ progs() places BPF_F_PREORDER programs at the front (ancestor cgroup first, attach order within a cgroup) and the rest after them (descendant cgroup first). So when a preorder program is present, the linear hlist position no longer equals the program's index in the effective array. For replace_effective_prog() (bpf_link_update()) this overwrote the wrong slot, corrupting the effective order. For purge_effective_progs(), it could dummy out a slot belonging to a different program and leave the detached program in the array while bpf_prog_put() drops its reference, i.e. a use-after-free. Fix both by replaying compute_effective_progs()'s placement (including the per-cgroup preorder reversal) in a shared effective_prog_pos() helper. Identify the entry by its struct bpf_prog_list pointer rather than by (prog, link) value, so the lookup resolves to exactly the attachment the syscall selected even when the same bpf_prog is attached to several cgroups in the hierarchy.

Gravité et risque d'exploitation

CVE-2026-72427 obtient un score CVSS de 7.8/10, soit une gravité élevée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.17 %, ce qui la place devant 6.0 % des CVE référencées.

Que faire ?

• Vérifiez si Linux (versions 7.1.5, bc8023ef3b11410682e5d4990e05e5bc2d3e1c94, 6.18.40, <=6.12.*, 0, <=7.1.*, 6.6.93, 6.14.9, <=6.6.*, 6.12.97, 555c0b713ca83968d3c843cb15485b9ba3367b1b, 4707ad649cf662add3058bff47430817811b048d, <=6.18.*, <525e408c27ae714e538b8c608c3a974df3ab6c92, <41b4320b84fdafe1ab586b06453d30d50415db59, 6.12.31, <b584f107ab90222bd825dcb4c5977326ff684109, 6.6.145, 6.15, 4b82b181a26cff8bf7adc3a85a88d121d92edeaf, <6.6.145, <=*, <f08aaee3152d0dfc578b3f2586932d82062701dd, <6.15, <6.12.97, <9697db03e010391c55ae75192cbdf30c5a72c114, 7.2) 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/525e408c27ae714e538b8c608c3a974df3ab6c92
• https://git.kernel.org/stable/c/41b4320b84fdafe1ab586b06453d30d50415db59
• https://git.kernel.org/stable/c/9697db03e010391c55ae75192cbdf30c5a72c114
• https://git.kernel.org/stable/c/b584f107ab90222bd825dcb4c5977326ff684109
• https://git.kernel.org/stable/c/f08aaee3152d0dfc578b3f2586932d82062701dd