CVE-2025-0031: SEV Firmware Use-After-Free Vulnerability

CVE-2025-0031 Overview

A use after free vulnerability exists in AMD's Secure Encrypted Virtualization (SEV) firmware that could allow a malicious hypervisor to activate a migrated guest with the SINGLE_SOCKET policy on a different socket than the migration agent, potentially resulting in loss of integrity. This vulnerability affects the secure VM migration process within AMD's confidential computing implementation.

Critical Impact
A malicious hypervisor could exploit this use after free condition to violate the SINGLE_SOCKET migration policy, potentially compromising the integrity guarantees of SEV-protected virtual machines during live migration operations.

Affected Products

AMD SEV Firmware (specific versions detailed in AMD-SB-3023)
AMD EPYC Processors with SEV support

Discovery Timeline

2026-02-10 - CVE CVE-2025-0031 published to NVD
2026-02-10 - Last updated in NVD database

Technical Details for CVE-2025-0031

Vulnerability Analysis

This vulnerability is classified as CWE-416 (Use After Free), a memory corruption issue where the SEV firmware continues to reference memory that has already been freed during the guest migration process. The flaw specifically impacts the enforcement of the SINGLE_SOCKET policy, which is designed to ensure that SEV-protected guests only execute on a single physical CPU socket for security isolation purposes.

When a guest VM configured with the SINGLE_SOCKET policy is migrated, the firmware should verify that the destination remains on the same socket as the migration agent. The use after free condition allows a malicious hypervisor to bypass this check, potentially activating the migrated guest on a different socket than intended.

Root Cause

The root cause lies in improper memory management within the SEV firmware's migration handling code. After certain migration-related data structures are freed, references to this memory are still used during the policy enforcement checks. This dangling pointer allows the hypervisor to manipulate the migration process by controlling the contents of the freed memory region before the subsequent access occurs.

Attack Vector

The attack requires local access and high privileges (hypervisor-level control). A malicious hypervisor operator could exploit this vulnerability by:

Initiating a migration of an SEV guest configured with SINGLE_SOCKET policy
Triggering the memory free operation in the firmware
Manipulating the freed memory region before the policy check occurs
Causing the guest to be activated on a different socket than the migration agent specified

This exploitation path requires a compromised or malicious hypervisor environment, limiting the attack surface to scenarios where the hypervisor itself is untrusted—a key threat model that SEV is designed to protect against.

Detection Methods for CVE-2025-0031

Indicators of Compromise

Unexpected SEV guest activations on sockets different from the configured migration agent
Anomalous memory access patterns during SEV guest migration operations
Policy violation alerts in hypervisor or firmware logs related to socket assignments

Detection Strategies

Monitor SEV firmware logs for unusual migration events or policy enforcement failures
Implement integrity monitoring for hypervisor components to detect tampering
Audit guest VM socket assignments post-migration against configured policies
Deploy hardware-based attestation to verify firmware integrity

Monitoring Recommendations

Enable verbose logging for SEV migration operations where available
Implement alerting for any SINGLE_SOCKET policy violations
Regularly review AMD security bulletins for firmware update notifications
Conduct periodic attestation checks on SEV-protected workloads

How to Mitigate CVE-2025-0031

Immediate Actions Required

Review the AMD Security Bulletin AMD-SB-3023 for specific remediation guidance
Apply the latest SEV firmware updates provided by AMD
Audit existing SEV guest configurations, particularly those using SINGLE_SOCKET policy
Consider temporarily disabling live migration for sensitive SEV workloads until patched

Patch Information

AMD has published security bulletin AMD-SB-3023 addressing this vulnerability. Organizations should obtain updated SEV firmware from AMD and follow vendor-specific guidance for their hardware platform. Firmware updates typically require coordination with the system vendor and may necessitate system downtime for installation.

For detailed patch information and affected product versions, refer to the AMD Security Bulletin AMD-SB-3023.

Workarounds

Avoid using live migration for SEV guests with SINGLE_SOCKET policy until firmware is updated
Restrict hypervisor access to trusted administrators only
Deploy additional monitoring around SEV migration operations
Consider using alternative security policies that do not rely on socket affinity if operationally feasible

bash

# Verify current SEV firmware version (platform-specific)
# Consult your system vendor documentation for exact commands
# Example for checking SEV status on Linux:
dmesg | grep -i sev
cat /sys/module/kvm_amd/parameters/sev