CVE-2025-29950: System Management Mode RCE Vulnerability

CVE-2025-29950 Overview

CVE-2025-29950 is a high-severity vulnerability affecting AMD System Management Mode (SMM) that arises from improper input validation. A privileged attacker with local access can exploit this flaw to overwrite stack memory, ultimately leading to arbitrary code execution within the highly privileged SMM context. System Management Mode operates at Ring -2 privilege level, making this vulnerability particularly dangerous as successful exploitation could bypass traditional security controls and compromise the entire system at a fundamental level.

Critical Impact

A privileged local attacker can achieve arbitrary code execution in SMM context, potentially compromising system integrity below the operating system level and bypassing firmware security mechanisms.

Affected Products

• AMD Processors (specific models detailed in AMD Security Bulletins)
• Systems utilizing AMD SMM implementations referenced in SB-3023
• Systems utilizing AMD SMM implementations referenced in SB-4013

Discovery Timeline

• 2026-02-10 - CVE-2025-29950 published to NVD
• 2026-02-10 - Last updated in NVD database

Technical Details for CVE-2025-29950

Vulnerability Analysis

This vulnerability is classified under CWE-1274 (Improper Access Control for Volatile Memory Containing Boot Code). The flaw exists within AMD's System Management Mode implementation, where insufficient validation of input parameters allows a privileged attacker to corrupt stack memory. SMM is one of the most privileged execution modes on x86 processors, operating independently of the operating system and hypervisor. Code running in SMM has unrestricted access to all system memory and hardware resources.

The attack requires local access and high privileges (such as administrator or root), along with high attack complexity to successfully exploit. However, once exploited, the impact is severe across confidentiality, integrity, and availability of the vulnerable system.

Root Cause

The root cause stems from improper input validation within SMM handler routines. When processing certain inputs, the SMM code fails to adequately validate parameters before using them in memory operations. This oversight allows carefully crafted inputs to trigger a stack buffer overflow condition, enabling an attacker to overwrite return addresses or other critical stack data.

Attack Vector

The attack vector is local, requiring the attacker to have existing privileged access to the target system. The exploitation path typically involves:

1. The attacker obtains high-privilege access (administrator/root) on the target system
2. The attacker triggers an SMM interrupt (System Management Interrupt - SMI) with maliciously crafted parameters
3. The SMM handler processes these parameters without proper bounds checking
4. Stack memory corruption occurs, allowing the attacker to redirect execution flow
5. Arbitrary code executes within the SMM context, achieving Ring -2 privilege

Due to the nature of SMM vulnerabilities, exploitation requires intimate knowledge of the firmware implementation and precise timing. No public proof-of-concept is currently available for this vulnerability.

Detection Methods for CVE-2025-29950

Indicators of Compromise

• Unexpected SMI (System Management Interrupt) activity patterns on affected AMD systems
• Anomalous firmware or BIOS modification attempts
• Unauthorized changes to SMM-protected memory regions
• Unexpected system behavior that cannot be attributed to OS-level processes

Detection Strategies

• Monitor for unusual SMI triggering patterns using hardware monitoring tools
• Implement firmware integrity verification using TPM-based attestation
• Deploy SentinelOne Singularity platform to detect suspicious privileged operations that may precede SMM exploitation
• Utilize UEFI Secure Boot to detect unauthorized firmware modifications

Monitoring Recommendations

• Enable firmware event logging where supported by the platform
• Implement baseline monitoring for SMI frequency and sources
• Deploy endpoint detection and response (EDR) solutions capable of monitoring kernel and driver activity
• Consider hardware-based security monitoring solutions for critical infrastructure

How to Mitigate CVE-2025-29950

Immediate Actions Required

• Review AMD Security Bulletin SB-3023 for specific guidance and affected products
• Review AMD Security Bulletin SB-4013 for additional details and firmware updates
• Apply firmware/BIOS updates from your system vendor that incorporate AMD's fixes
• Restrict local administrator access to minimize the attack surface

Patch Information

AMD has released security advisories addressing this vulnerability. System administrators should contact their OEM or motherboard vendor for BIOS/UEFI firmware updates that incorporate the necessary SMM fixes. Firmware updates typically require a system reboot and should be tested in non-production environments before deployment.

Refer to the official AMD security bulletins for detailed patch information:

• AMD Security Bulletin SB-3023
• AMD Security Bulletin SB-4013

Workarounds

• Enforce strict access control policies limiting local administrator privileges
• Implement hardware-based security features such as TPM and Secure Boot to detect unauthorized firmware changes
• Deploy SentinelOne Singularity to monitor for suspicious privileged activity that may indicate exploitation attempts
• Consider network segmentation to limit lateral movement from compromised systems

Since this is a firmware-level vulnerability, software-only mitigations are limited. The primary mitigation is applying vendor-provided firmware updates. In environments where immediate patching is not feasible, reducing the attack surface by limiting privileged access is essential.