CVE-2025-29948: AMD SEV Privilege Escalation Vulnerability

CVE-2025-29948 Overview

CVE-2025-29948 is an improper access control vulnerability in AMD Secure Encrypted Virtualization (SEV) firmware that could allow a malicious hypervisor to bypass Reverse Map Table (RMP) protections. This vulnerability potentially results in a loss of SEV-SNP (Secure Nested Paging) guest memory integrity, undermining the security guarantees that SEV-SNP is designed to provide.

Critical Impact

A malicious hypervisor could bypass RMP protections designed to isolate and protect guest virtual machine memory, potentially compromising the integrity of confidential computing workloads running on affected AMD processors.

Affected Products

• AMD Secure Encrypted Virtualization (SEV) firmware
• Systems utilizing AMD SEV-SNP technology
• AMD processors with SEV-SNP support

Discovery Timeline

• 2026-02-10 - CVE CVE-2025-29948 published to NVD
• 2026-02-10 - Last updated in NVD database

Technical Details for CVE-2025-29948

Vulnerability Analysis

This vulnerability affects AMD's Secure Encrypted Virtualization (SEV) technology, specifically the SEV-SNP (Secure Nested Paging) implementation. SEV-SNP is designed to provide strong isolation between virtual machines and the hypervisor by encrypting guest memory and using the Reverse Map Table (RMP) to enforce memory access controls.

The improper access control flaw (CWE-1260: Improper Handling of Overlap Between Protected Memory Ranges) allows a malicious hypervisor to circumvent RMP protections. Under normal circumstances, the RMP prevents the hypervisor from reading or modifying guest memory without proper authorization. This vulnerability breaks that security boundary, potentially allowing an attacker with hypervisor-level access to compromise the integrity of guest VM memory.

Root Cause

The root cause stems from improper handling of overlap between protected memory ranges (CWE-1260) within the SEV firmware. This classification indicates that the firmware fails to properly validate or enforce protections when memory range overlaps occur, creating a window where RMP protections can be bypassed. The vulnerability exists at the firmware level, meaning it affects the foundational security mechanisms of the SEV-SNP architecture.

Attack Vector

The attack requires local access with high privileges (hypervisor-level access). A malicious cloud provider, compromised hypervisor, or attacker who has gained hypervisor control could exploit this vulnerability to bypass the memory isolation guarantees provided by SEV-SNP. The exploitation does not require user interaction and can be performed without complex preconditions once hypervisor access is achieved.

The attack targets the integrity of guest memory rather than confidentiality or availability directly. By bypassing RMP protections, an attacker could potentially modify guest memory contents, inject malicious code, or tamper with data being processed within what the guest believes to be a protected environment.

Detection Methods for CVE-2025-29948

Indicators of Compromise

• Unexpected modifications to SEV-SNP guest memory that cannot be attributed to legitimate guest operations
• Anomalous RMP validation failures or inconsistencies in firmware logs
• Unusual hypervisor behavior patterns when interacting with SEV-SNP protected guests

Detection Strategies

• Monitor AMD firmware version deployments across infrastructure to identify unpatched systems
• Implement attestation verification for SEV-SNP guests to detect integrity violations
• Enable verbose logging on hypervisor platforms to capture potential exploitation attempts
• Deploy integrity monitoring solutions that can detect unauthorized memory modifications

Monitoring Recommendations

• Review AMD security bulletins regularly and subscribe to AMD product security notifications
• Implement continuous firmware version inventory tracking for AMD processors
• Establish baseline behavior patterns for SEV-SNP workloads to detect anomalies
• Monitor for unauthorized or unexpected attestation report requests

How to Mitigate CVE-2025-29948

Immediate Actions Required

• Review AMD Security Bulletin #3023 for specific affected products and firmware versions
• Inventory all systems utilizing AMD SEV-SNP technology to identify potentially vulnerable deployments
• Prioritize firmware updates for systems hosting sensitive or confidential computing workloads
• Assess risk based on threat model and whether hypervisor compromise is a considered threat

Patch Information

AMD has released information regarding this vulnerability in AMD Security Bulletin #3023. Organizations should consult this bulletin for specific firmware update instructions, affected processor models, and detailed remediation guidance. Coordinate with your hardware vendor or cloud service provider to ensure appropriate firmware updates are applied.

Workarounds

• Implement additional monitoring and access controls around hypervisor management interfaces
• Restrict hypervisor access to only trusted administrators with strong authentication requirements
• Consider workload placement policies that isolate highly sensitive workloads from potentially compromised hypervisor environments
• Evaluate alternative isolation technologies as defense-in-depth measures while awaiting firmware updates

# Verify AMD SEV-SNP status and firmware version (Linux)
# Check if SEV-SNP is enabled
dmesg | grep -i "SEV-SNP"

# Verify AMD microcode version
cat /proc/cpuinfo | grep -i "microcode"

# Check SEV firmware version (requires root)
cat /sys/kernel/debug/ccp/*/psp-firmware-version 2>/dev/null