CVE-2023-31309 Overview
CVE-2023-31309 is an improper input validation vulnerability (CWE-129) in AMD Power Management Firmware (PMFW). The flaw allows a privileged local attacker to pass malformed workload arguments when the System Management Unit (SMU) exports table data to Dynamic Random Access Memory (DRAM). Successful exploitation can lead to a loss of confidentiality and availability on affected systems.
The vulnerability requires local access and high privileges, limiting practical exploitation scenarios. AMD disclosed the issue in AMD Security Bulletin #6027.
Critical Impact
A privileged local attacker can supply malformed workload arguments to PMFW, causing the SMU to expose sensitive data or degrade system availability during table export operations to DRAM.
Affected Products
- AMD processors implementing Power Management Firmware (PMFW)
- AMD System Management Unit (SMU) firmware components
- See AMD Security Bulletin #6027 for the full list of impacted platforms and firmware versions
Discovery Timeline
- 2026-05-15 - CVE-2023-31309 published to NVD
- 2026-05-15 - Last updated in NVD database
Technical Details for CVE-2023-31309
Vulnerability Analysis
The vulnerability resides in the validation logic of AMD Power Management Firmware (PMFW). PMFW is firmware running on the System Management Unit (SMU), an embedded microcontroller inside AMD processors. The SMU coordinates power, thermal, and voltage management for the CPU and GPU.
During normal operation, the SMU exports telemetry and workload table data to host-accessible DRAM. PMFW accepts workload arguments from privileged software interfaces. The firmware fails to properly validate these arguments before using them in the export routine.
Malformed workload arguments can cause the SMU to read or write outside of intended bounds during the DRAM transfer. This results in exposure of firmware-managed memory contents or disruption of the power management subsystem. The issue is categorized as improper validation of array index [CWE-129].
Root Cause
PMFW does not enforce strict bounds and type checking on workload arguments supplied through privileged interfaces. The firmware trusts caller-supplied indices and parameters when assembling table data for export. Crafted values steer the SMU into accessing memory regions that should remain inaccessible to the caller, or into states that interrupt power management services.
Attack Vector
Exploitation requires local access with high privileges, such as a kernel-mode driver, hypervisor component, or administrative process able to interact with the SMU mailbox interface. A remote network attacker cannot directly reach the vulnerable code path. User interaction is not required.
An attacker first obtains privileged execution on the host, then issues SMU commands containing malformed workload arguments to trigger the flawed export path. Because no public proof-of-concept exists and the EPSS probability is 0.017%, in-the-wild exploitation is unlikely. See AMD Security Bulletin #6027 for technical details.
Detection Methods for CVE-2023-31309
Indicators of Compromise
- Unexpected kernel-mode or hypervisor-level processes issuing SMU mailbox commands outside of standard vendor utilities
- Anomalous reads of PMFW-exported DRAM telemetry regions by non-standard drivers
- System instability, unexpected power state transitions, or SMU watchdog resets following privileged operations
Detection Strategies
- Monitor loaded kernel drivers and signed driver inventory for unauthorized components capable of interacting with AMD SMU interfaces
- Baseline legitimate vendor tooling (such as AMD Ryzen Master, OEM management agents) and alert on deviations
- Correlate Endpoint Detection and Response (EDR) telemetry with hardware error logs and Windows Hardware Error Architecture (WHEA) events
Monitoring Recommendations
- Audit privileged process creation and driver load events, focusing on processes that access \\.\PhysicalMemory or vendor SMU IOCTLs
- Track firmware and microcode versions across the fleet and flag systems running pre-fix PMFW builds
- Forward kernel and platform event logs to a centralized Security Information and Event Management (SIEM) for long-term analysis
How to Mitigate CVE-2023-31309
Immediate Actions Required
- Identify systems with affected AMD processors by consulting AMD Security Bulletin #6027
- Apply BIOS, UEFI, or platform firmware updates from the system OEM that include the patched PMFW
- Restrict administrative and kernel-mode access to authorized personnel only, since exploitation requires high privileges
- Enforce signed driver requirements and Hypervisor-Protected Code Integrity (HVCI) where supported
Patch Information
AMD has released updated Power Management Firmware addressing the improper validation issue. Patched PMFW is delivered through OEM BIOS and UEFI firmware updates. Consult your system vendor for the specific firmware revision that incorporates the fix for CVE-2023-31309, and reference AMD Security Bulletin #6027 for affected product mappings.
Workarounds
- Limit local administrator and root accounts to reduce the population of users able to reach the SMU interface
- Block installation of unsigned or unvetted drivers that expose SMU mailbox functionality to user-space callers
- Apply principle of least privilege to management agents and overclocking utilities that communicate with PMFW
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
