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CVE-2025-38591

Vulnérabilité non évaluée dans Linux (Linux)

CVSS 0.0 · Non évaluée
EPSS 0.2%
Linux•Linux•Versions : <=6.1.*, <=6.12.*, <=6.16.*, 6.17, 0, <202900ceeef67458c964c2af6e1427c8e533ea7c, 6.12.67, 5.15.199, <33660d44e789edb4f303210c813fc56d56377a90, <feae34c992eb7191862fb1594c704fbbf650fef8, <=5.10.*, <=6.6.*, 6.16.1, 4.13, 6.6.157, 5.10.249, 6.1.162, <4.13, <e09299225d5ba3916c91ef70565f7d2187e4cca0, <=*, f96da09473b52c09125cc9bf7d7d4576ae8229e0, <=5.15.*, <e2e9599f3503df7cf3569d2b6c50d5488fb59435, <7847c4140e06f6e87229faae22cc38525334c156, <058a0da4f6d916a79b693384111bb80a90d73763

Description

In the Linux kernel, the following vulnerability has been resolved: bpf: Reject narrower access to pointer ctx fields The following BPF program, simplified from a syzkaller repro, causes a kernel warning: r0 = *(u8 *)(r1 + 169); exit; With pointer field sk being at offset 168 in __sk_buff. This access is detected as a narrower read in bpf_skb_is_valid_access because it doesn't match offsetof(struct __sk_buff, sk). It is therefore allowed and later proceeds to bpf_convert_ctx_access. Note that for the "is_narrower_load" case in the convert_ctx_accesses(), the insn->off is aligned, so the cnt may not be 0 because it matches the offsetof(struct __sk_buff, sk) in the bpf_convert_ctx_access. However, the target_size stays 0 and the verifier errors with a kernel warning: verifier bug: error during ctx access conversion(1) This patch fixes that to return a proper "invalid bpf_context access off=X size=Y" error on the load instruction. The same issue affects multiple other fields in context structures that allow narrow access. Some other non-affected fields (for sk_msg, sk_lookup, and sockopt) were also changed to use bpf_ctx_range_ptr for consistency. Note this syzkaller crash was reported in the "Closes" link below, which used to be about a different bug, fixed in commit fce7bd8e385a ("bpf/verifier: Handle BPF_LOAD_ACQ instructions in insn_def_regno()"). Because syzbot somehow confused the two bugs, the new crash and repro didn't get reported to the mailing list.

Gravité et risque d'exploitation

CVE-2025-38591 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 0.21 %, ce qui la place devant 10.6 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions <=6.1.*, <=6.12.*, <=6.16.*, 6.17, 0, <202900ceeef67458c964c2af6e1427c8e533ea7c, 6.12.67, 5.15.199, <33660d44e789edb4f303210c813fc56d56377a90, <feae34c992eb7191862fb1594c704fbbf650fef8, <=5.10.*, <=6.6.*, 6.16.1, 4.13, 6.6.157, 5.10.249, 6.1.162, <4.13, <e09299225d5ba3916c91ef70565f7d2187e4cca0, <=*, f96da09473b52c09125cc9bf7d7d4576ae8229e0, <=5.15.*, <e2e9599f3503df7cf3569d2b6c50d5488fb59435, <7847c4140e06f6e87229faae22cc38525334c156, <058a0da4f6d916a79b693384111bb80a90d73763) 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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