CVE-2026-43265
Vulnérabilité non évaluée dans Linux (Linux)
Description
In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Ignore -EBUSY when checking nested events from vcpu_block() Ignore -EBUSY when checking nested events after exiting a blocking state while L2 is active, as exiting to userspace will generate a spurious userspace exit, usually with KVM_EXIT_UNKNOWN, and likely lead to the VM's demise. Continuing with the wakeup isn't perfect either, as *something* has gone sideways if a vCPU is awakened in L2 with an injected event (or worse, a nested run pending), but continuing on gives the VM a decent chance of surviving without any major side effects. As explained in the Fixes commits, it _should_ be impossible for a vCPU to be put into a blocking state with an already-injected event (exception, IRQ, or NMI). Unfortunately, userspace can stuff MP_STATE and/or injected events, and thus put the vCPU into what should be an impossible state. Don't bother trying to preserve the WARN, e.g. with an anti-syzkaller Kconfig, as WARNs can (hopefully) be added in paths where _KVM_ would be violating x86 architecture, e.g. by WARNing if KVM attempts to inject an exception or interrupt while the vCPU isn't running.
Gravité et risque d'exploitation
CVE-2026-43265 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 0.16 %, ce qui la place devant 5.1 % des CVE référencées.
Que faire ?
- Vérifiez si Linux (versions <=6.1.*, <=6.12.*, <78265cd066d73a5cb41c088fcae4a2515e480d97, 0, 7.0, 6.18.17, <2657439265d34a911886b916ba8be97ecc117d51, <=6.6.*, <=6.19.*, <ead63640d4e72e6f6d464f4e31f7fecb79af8869, <1c957773063ed3264953597e32990a748381caf6, <=6.18.*, <1e88b5f854bdb469424132e0bb44793ad7a7c20a, 6.1.167, <ec3be7dc9391085a2d96700e159d66d1328b7ff6, 6.1, 6.19.6, <=*, 6.12.77, 6.6.130, <6.1, 26844fee6adee9b1557d2279b0506285de9ee82b) 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/78265cd066d73a5cb41c088fcae4a2515e480d97
- https://git.kernel.org/stable/c/ec3be7dc9391085a2d96700e159d66d1328b7ff6
- https://git.kernel.org/stable/c/2657439265d34a911886b916ba8be97ecc117d51
- https://git.kernel.org/stable/c/1e88b5f854bdb469424132e0bb44793ad7a7c20a
- https://git.kernel.org/stable/c/1c957773063ed3264953597e32990a748381caf6
- https://git.kernel.org/stable/c/ead63640d4e72e6f6d464f4e31f7fecb79af8869