CVE-2023-31316: AMD Secure Processor Privilege Escalation

CVE-2023-31316 Overview

CVE-2023-31316 is a hardware integrity vulnerability in the AMD Secure Processor (ASP). The flaw stems from improperly preserved integrity of hardware configuration state during a power save/restore operation. An attacker with the ability to write outside the Trusted Memory Range (TMR) can alter the execution flow of the Video Core Next (VCN) firmware. Successful exploitation impacts confidentiality, integrity, and availability of the affected system. The weakness is tracked under [CWE-1304] (Improperly Preserved Integrity of Hardware Configuration State During a Power Save/Restore Operation).

Critical Impact

Local attackers with low privileges can manipulate VCN firmware execution flow by tampering with hardware state preserved across power state transitions, undermining trusted execution guarantees.

Affected Products

• AMD Secure Processor (ASP) firmware components
• AMD Video Core Next (VCN) firmware
• AMD platforms enumerated in AMD Security Bulletin #4017 and AMD Security Bulletin #6027

Discovery Timeline

• 2026-05-15 - CVE-2023-31316 published to NVD
• 2026-05-15 - Last updated in NVD database

Technical Details for CVE-2023-31316

Vulnerability Analysis

The vulnerability resides in how the AMD Secure Processor handles hardware configuration state across power save and restore transitions. During these transitions, the ASP must serialize and later restore configuration state for downstream IP blocks, including the Video Core Next firmware engine. The integrity of this preserved state is not adequately enforced. An attacker who can write outside the Trusted Memory Range can modify the saved state before restoration occurs. When the ASP restores that state, the manipulated values are loaded into VCN firmware control structures. This shifts the firmware execution flow into attacker-influenced paths, breaking the security boundary that the ASP is designed to provide.

Root Cause

The root cause is classified under [CWE-1304]. The ASP firmware does not cryptographically verify or otherwise integrity-protect hardware configuration state stored outside the TMR during low-power transitions. Because the storage region used for save/restore is reachable by code with sufficient local write capability, the integrity assumption is violated. Trusted state and untrusted memory are conflated during the restore sequence.

Attack Vector

Exploitation requires local access with low privileges and high attack complexity. The attacker must time writes against the power save/restore sequence and target memory regions outside the TMR that participate in VCN firmware configuration. Network exploitation and user interaction are not required. Successful manipulation diverts VCN firmware execution, which can be leveraged to compromise integrity-sensitive operations, leak protected media or content paths, or disrupt availability.

No verified exploit code is available. The vulnerability is described in detail in the AMD security bulletins listed under references. See the AMD Security Bulletin #4017 for affected platforms and firmware versions.

Detection Methods for CVE-2023-31316

Indicators of Compromise

• Unexpected VCN firmware behavior, including media decode anomalies or unexplained crashes following system resume from sleep or hibernation states.
• Kernel logs reporting ASP or PSP communication errors after power transitions on AMD platforms.
• Firmware version strings that do not match the fixed versions enumerated in the AMD security bulletins.

Detection Strategies

• Inventory AMD platform firmware versions across endpoints and compare against the fixed builds listed by AMD.
• Monitor for privileged local processes performing writes to physical memory ranges adjacent to the configured TMR.
• Correlate suspend/resume events with subsequent abnormal GPU or media subsystem telemetry.

Monitoring Recommendations

• Enable boot integrity and firmware measurement logging through platform attestation features.
• Centralize firmware inventory and power-state event telemetry in a SIEM for longitudinal analysis.
• Alert on driver or kernel modules that interact with ASP mailbox interfaces from unsigned or unexpected code paths.

How to Mitigate CVE-2023-31316

Immediate Actions Required

• Apply the AMD firmware and AGESA updates referenced in AMD Security Bulletin #4017 and AMD Security Bulletin #6027 as soon as OEM-validated builds are available.
• Restrict local administrative access on affected AMD platforms to reduce the population of users able to perform out-of-TMR writes.
• Validate that BIOS/UEFI settings enforce secure boot and memory protection features supported by the platform.

Patch Information

AMD has published fixed firmware versions through its OEM partners. Refer to AMD Security Bulletin #4017 and AMD Security Bulletin #6027 for the authoritative list of affected products and the minimum patched firmware or AGESA versions. Deploy updates through the system vendor's standard firmware update mechanism.

Workarounds

• No vendor-supplied workaround replaces the firmware patch. AMD's guidance is to update to fixed firmware.
• Disable or limit features that depend on VCN firmware on systems that cannot be patched, where operationally acceptable.
• Enforce least privilege and application allowlisting to limit local code with the capability to target memory outside the TMR.

# Example: enumerate AMD platform firmware versions on Linux for patch tracking
sudo dmidecode -t bios | grep -E 'Vendor|Version|Release Date'
cat /sys/class/dmi/id/bios_version