The vulnerability is a race condition in the Linux kernel’s x86/virt SEV‑ES code caused by removing the required WBINVD instruction before initializing the Secure Nested Paging (SNP) RMP table. Because CPU caches were no longer flushed when the RMP was loaded, dirty cache lines could remain visible to a guest VM that had not yet been protected by firmware, allowing a malicious VM to read memory it should not access. This represents a serious information‑leakage weakness, corresponding to CWE-366.

All Linux kernel installations that enable AMD SEV‑ES virtualization on processors supporting the AMD64 SNP feature are affected. The defect exists in the generic x86/virt module and applies whenever SEV‑ES is active, regardless of the specific kernel version. Versions are not restricted in the advisory, so every recent kernel that supports SEV‑ES on compatible hardware is potentially vulnerable.

The CVSS score of 9.3 indicates a critical severity, yet the EPSS score of <1% and the absence from CISA KEV suggest a low likelihood of exploitation. The likely attack vector is inferred to involve a malicious guest attempting to time inter‑processor interrupts and the cache flush during SNP initialization to capture dirty data; this inference is not explicitly stated in the CVE data. Practical exploitation would require precise timing of a race condition, making it difficult but not impossible, and thus the overall risk remains high for environments that rely on SEV‑ES for isolation.