x86/vmscape: Add conditional IBPB mitigation (Linux Linux)

CVE-2025-40300
MEDIUM 5.5

En bref

Source
NVD
EPSS
EPSS 0.38 % · centile 32 ()
État
PUBLISHED
Publiée
Mise à jour
Attribuée par
Linux
Statut NVD
Modified

Description

In the Linux kernel, the following vulnerability has been resolved: x86/vmscape: Add conditional IBPB mitigation VMSCAPE is a vulnerability that exploits insufficient branch predictor isolation between a guest and a userspace hypervisor (like QEMU). Existing mitigations already protect kernel/KVM from a malicious guest. Userspace can additionally be protected by flushing the branch predictors after a VMexit. Since it is the userspace that consumes the poisoned branch predictors, conditionally issue an IBPB after a VMexit and before returning to userspace. Workloads that frequently switch between hypervisor and userspace will incur the most overhead from the new IBPB. This new IBPB is not integrated with the existing IBPB sites. For instance, a task can use the existing speculation control prctl() to get an IBPB at context switch time. With this implementation, the IBPB is doubled up: one at context switch and another before running userspace. The intent is to integrate and optimize these cases post-embargo. [ dhansen: elaborate on suboptimal IBPB solution ]

Références

Scores

VersionScoreVecteurÉvalué par
CVSS 3.1MEDIUM 5.5CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HNVD · nvd@nist.gov (Primary)

Références européennes

Avis du CERT-FR

Configurations affectées (CPE NVD)

Produits affectés

ProduitVersions
Linux · Linuxaffected 15d45071523d89b3fb7372e2135fbd72f6af9506 < ac60717f9a8d21c58617d0b34274babf24135835 ; affected 15d45071523d89b3fb7372e2135fbd72f6af9506 < c08192b5d6730a914dee6175bc71092ee6a65f14 ; affected 15d45071523d89b3fb7372e2135fbd72f6af9506 < d5490dfa35427a2967e00a4c7a1b95fdbc8ede34 ; affected 15d45071523d89b3fb7372e2135fbd72f6af9506 < 2f4f2f8f860cb4c3336a7435ebe8dcfded0c9c6e ; affected 15d45071523d89b3fb7372e2135fbd72f6af9506 < 15006289e5c38b2a830e1fba221977a27598176c ; affected 15d45071523d89b3fb7372e2135fbd72f6af9506 < 893387c18612bb452336a5881da0d015a7e8f4a2
Linux · Linuxaffected 4.16 ; unaffected 0 < 4.16 ; unaffected 5.10.244 ≤ 5.10.* ; unaffected 5.15.193 ≤ 5.15.* ; unaffected 6.1.152 ≤ 6.1.* ; unaffected 6.6.106 ≤ 6.6.*

Sources

SourceLicence
CVE List (CVEProject cvelistV5)CVE Program Terms of Use
EPSS (FIRST.org)FIRST — attribution requested
ENISA EUVDENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feedsPublic domain — this product uses data from the NVD API but is not endorsed or certified by the NVD