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CVE-2025-39748

Vulnérabilité non évaluée dans Linux (Linux)

CVSS 0.0 · Non évaluée
EPSS 0.2%
Linux•Linux•Versions : <=6.1.*, <2fd0c26bacd90ef26522bd3169000a4715bf151f, <=6.12.*, <f01e06930444cab289a8783017af9b64255bd103, <6279846b9b2532e1b04559ef8bd0dec049f29383, <=6.16.*, 6.17, 0, 960ea056561a08e2b837b2f02d22c53226414a84, <=6.15.*, <=5.10.*, <=6.6.*, 5.0, 5.15.203, 6.12.43, <5.0, 6.1.167, 6.16.2, <80a6b11862a7cfdf691e8f9faee89cfea219f098, <591c788d16046edb0220800bf1819554af5853ce, <=*, 5.10.253, <=5.15.*, <c29dd8336236a4deb75596b52d2dd16ccc4a380d, <22191359f8454b0be082c3b126f86bcbea0f1318, <0643aa2468192a4d81326e8e76543854870b1ee2, 6.6.130, 6.15.11

Description

In the Linux kernel, the following vulnerability has been resolved: bpf: Forget ranges when refining tnum after JSET Syzbot reported a kernel warning due to a range invariant violation on the following BPF program. 0: call bpf_get_netns_cookie 1: if r0 == 0 goto <exit> 2: if r0 & Oxffffffff goto <exit> The issue is on the path where we fall through both jumps. That path is unreachable at runtime: after insn 1, we know r0 != 0, but with the sign extension on the jset, we would only fallthrough insn 2 if r0 == 0. Unfortunately, is_branch_taken() isn't currently able to figure this out, so the verifier walks all branches. The verifier then refines the register bounds using the second condition and we end up with inconsistent bounds on this unreachable path: 1: if r0 == 0 goto <exit> r0: u64=[0x1, 0xffffffffffffffff] var_off=(0, 0xffffffffffffffff) 2: if r0 & 0xffffffff goto <exit> r0 before reg_bounds_sync: u64=[0x1, 0xffffffffffffffff] var_off=(0, 0) r0 after reg_bounds_sync: u64=[0x1, 0] var_off=(0, 0) Improving the range refinement for JSET to cover all cases is tricky. We also don't expect many users to rely on JSET given LLVM doesn't generate those instructions. So instead of improving the range refinement for JSETs, Eduard suggested we forget the ranges whenever we're narrowing tnums after a JSET. This patch implements that approach.

Gravité et risque d'exploitation

CVE-2025-39748 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 0.17 %, ce qui la place devant 6.4 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions <=6.1.*, <2fd0c26bacd90ef26522bd3169000a4715bf151f, <=6.12.*, <f01e06930444cab289a8783017af9b64255bd103, <6279846b9b2532e1b04559ef8bd0dec049f29383, <=6.16.*, 6.17, 0, 960ea056561a08e2b837b2f02d22c53226414a84, <=6.15.*, <=5.10.*, <=6.6.*, 5.0, 5.15.203, 6.12.43, <5.0, 6.1.167, 6.16.2, <80a6b11862a7cfdf691e8f9faee89cfea219f098, <591c788d16046edb0220800bf1819554af5853ce, <=*, 5.10.253, <=5.15.*, <c29dd8336236a4deb75596b52d2dd16ccc4a380d, <22191359f8454b0be082c3b126f86bcbea0f1318, <0643aa2468192a4d81326e8e76543854870b1ee2, 6.6.130, 6.15.11) 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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