CVE-2026-72239

Received Received - Intake

Revert SEV WBINVD Fix in Linux Kernel

Publication date: 2026-08-15

Last updated on: 2026-08-17

Assigner: kernel.org

Description

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. ]

CVSS Scores

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Meta Information

Published

2026-08-15

Last Modified

2026-08-17

Generated

2026-09-04

AI Q&A

2026-08-15

EPSS Evaluated

2026-09-03

NVD

CVE-2026-72239

EUVD

EUVD-2026-59138

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability in the Linux kernel involves a missing cache flush operation before enabling AMD Secure Nested Paging (SNP) in SEV (Secure Encrypted Virtualization). The issue occurs when cache lines with dirty data are not properly flushed before the RMP (Reverse Map Table) is initialized, violating firmware requirements.

Detection Guidance

This vulnerability is specific to the Linux kernel's SEV (Secure Encrypted Virtualization) implementation. Detection requires checking the kernel version and SEV-related configurations. Use commands like 'uname -a' to check the kernel version and 'dmesg | grep -i sev' to look for SEV-related messages. If the kernel is older than the patched version, the system may be vulnerable.

Impact Analysis

This vulnerability could allow a malicious actor to exploit improper cache management to access sensitive memory or bypass security protections in virtualized environments using AMD SEV.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR, HIPAA, or similar standards. It is a low-level hardware security issue in the Linux kernel related to AMD SEV-SNP (Secure Encrypted Virtualization) cache management, which could lead to memory corruption if exploited. Compliance impacts would only occur if this vulnerability were exploited to compromise data integrity or confidentiality in a system handling regulated data.

Mitigation Strategies

Update the Linux kernel to the latest patched version that includes the revert of the problematic commit. Reboot the system after applying the update to ensure the new kernel is active. Monitor SEV-related logs for any unusual activity post-update.

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