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CVE-2026-31593

Vulnérabilité non évaluée dans Linux (Linux)

CVSS 0.0 · Non évaluée
EPSS 0.2%
Linux•Linux•Versions : <=7.0.*, <=6.12.*, 0, 6.12.83, 7.0.1, ad27ce155566f2b4400fa865859834592bd18777, <c9609847ae65ca36233077c2b6cb2bc0fb37c77a, <=6.19.*, <9b9f7962e3e879d12da2bf47e02a24ec51690e3d, 7.1, <=6.18.*, <6.11, 6.11, <=*, 6.19.14, 6.18.24, <6ef109e01e1d35199e1a97ea68bdfd3cf3fbf9ab, <8f85a4885eee8cb495961ffa371a91828afb9445, <692fdf05e55fa03960a1278afdc2478c12daea13

Description

In the Linux kernel, the following vulnerability has been resolved: KVM: SEV: Reject attempts to sync VMSA of an already-launched/encrypted vCPU Reject synchronizing vCPU state to its associated VMSA if the vCPU has already been launched, i.e. if the VMSA has already been encrypted. On a host with SNP enabled, accessing guest-private memory generates an RMP #PF and panics the host. BUG: unable to handle page fault for address: ff1276cbfdf36000 #PF: supervisor write access in kernel mode #PF: error_code(0x80000003) - RMP violation PGD 5a31801067 P4D 5a31802067 PUD 40ccfb5063 PMD 40e5954063 PTE 80000040fdf36163 SEV-SNP: PFN 0x40fdf36, RMP entry: [0x6010fffffffff001 - 0x000000000000001f] Oops: Oops: 0003 [#1] SMP NOPTI CPU: 33 UID: 0 PID: 996180 Comm: qemu-system-x86 Tainted: G OE Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE Hardware name: Dell Inc. PowerEdge R7625/0H1TJT, BIOS 1.5.8 07/21/2023 RIP: 0010:sev_es_sync_vmsa+0x54/0x4c0 [kvm_amd] Call Trace: <TASK> snp_launch_update_vmsa+0x19d/0x290 [kvm_amd] snp_launch_finish+0xb6/0x380 [kvm_amd] sev_mem_enc_ioctl+0x14e/0x720 [kvm_amd] kvm_arch_vm_ioctl+0x837/0xcf0 [kvm] kvm_vm_ioctl+0x3fd/0xcc0 [kvm] __x64_sys_ioctl+0xa3/0x100 x64_sys_call+0xfe0/0x2350 do_syscall_64+0x81/0x10f0 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7ffff673287d </TASK> Note, the KVM flaw has been present since commit ad73109ae7ec ("KVM: SVM: Provide support to launch and run an SEV-ES guest"), but has only been actively dangerous for the host since SNP support was added. With SEV-ES, KVM would "just" clobber guest state, which is totally fine from a host kernel perspective since userspace can clobber guest state any time before sev_launch_update_vmsa().

Gravité et risque d'exploitation

CVE-2026-31593 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 5.0 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions <=7.0.*, <=6.12.*, 0, 6.12.83, 7.0.1, ad27ce155566f2b4400fa865859834592bd18777, <c9609847ae65ca36233077c2b6cb2bc0fb37c77a, <=6.19.*, <9b9f7962e3e879d12da2bf47e02a24ec51690e3d, 7.1, <=6.18.*, <6.11, 6.11, <=*, 6.19.14, 6.18.24, <6ef109e01e1d35199e1a97ea68bdfd3cf3fbf9ab, <8f85a4885eee8cb495961ffa371a91828afb9445, <692fdf05e55fa03960a1278afdc2478c12daea13) 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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