CVE-2026-72239
CriticalCVSS 9.3Exploitation Probability (EPSS)
Low risk9th percentile - higher than 9% of all known CVEs
Summary
In the Linux kernel x86/virt/sev subsystem, a previous fix regarding WBINVD before setting MSR_AMD64_SYSCFG_SNP_EN was reverted. The call to wbinvd_on_all_cpus() before SNP_INIT_EX was restored to meet SNP specification requirements for clean cache lines.
Risk Assessment
Lack of proper cache flushing may violate SNP firmware requirements, potentially leading to incorrect secure processing (SNP) behavior and security issues.
Recommendation
It is recommended to update the Linux kernel to a version containing the fix and test SNP functionality in a test environment.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: x86/virt/sev: Revert "Drop WBINVD before setting MSR_AMD64_SYSCFG_SNP_EN" Revert 99cf1fb58e68 ("x86/virt/sev: Drop WBINVD before setting MSR_AMD64_SYSCFG_SNP_EN"). Section 8.8 of the SNP spec says: Before invoking SNP_INIT_EX with INIT_RMP set to 1, software must ensure that no CPUs contain dirty cache lines for the memory containing the RMP. Cachelines can be moved from cache to cache in a dirty state. The wbinvd_on_all_cpus() before SNP_INIT_EX flushes the caches for each CPU, but if the IPIs for WBINVD race with this dirty cacheline movement, it is possible that they may not get flushed, violating the firmware requirement. Doing wbinvd_on_all_cpus() before setting SNPEn is safer since the RMP table is not yet in use. [ Heroically bisected by Srikanth. ] [ bp: Massage commit message. ]