CVE-2023-4155: Sev-es / sev-snp vmgexit double fetch vulnerability

Severity: medium (CVSS 5.6 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-09-13 · updated 2026-06-17
Weakness: CWE-367

Description

A flaw was found in KVM AMD Secure Encrypted Virtualization (SEV) in the Linux kernel. A KVM guest using SEV-ES or SEV-SNP with multiple vCPUs can trigger a double fetch race condition vulnerability and invoke the `VMGEXIT` handler recursively. If an attacker manages to call the handler multiple times, they can trigger a stack overflow and cause a denial of service or potentially guest-to-host escape in kernel configurations without stack guard pages (`CONFIG_VMAP_STACK`).

Affected products

Fedoraproject Fedora: 37, 38
Linux kernel: all versions
Red Hat Enterprise Linux: 8.0, 9.0

References

https://access.redhat.com/security/cve/CVE-2023-4155
https://bugzilla.redhat.com/show_bug.cgi?id=2213802
https://access.redhat.com/security/cve/CVE-2023-4155
https://bugzilla.redhat.com/show_bug.cgi?id=2213802

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