AMD AGESA Bootloader Firmware CVE-2025-48516

Local system access with standard user privileges is required - the attacker must have a valid user account or shell on the target system. The PMIC interface must be exposed through AGESA Bootloader Firmware with default access controls, which is the case for all shipped versions of affected Ryzen processor families listed. No authentication beyond local OS login is needed. The vulnerability is not conditional on specific BIOS settings or non-default configurations - exploitation is possible on out-of-the-box systems. However, exploitation is limited to local context: remote attackers cannot trigger this vulnerability, and network-based exploitation is impossible. Physical access to the system is not strictly required but facilitates exploitation (e.g., via BIOS/recovery mode access). Systems with OS-level access controls restricting user shell access or disabling firmware interaction tools are partially mitigated.

CVSS 6.9 with local attack vector (AV:L), low complexity (AC:L), and low privileges (PR:L) indicates real but bounded risk. The vulnerability requires local system access and legitimate user account - it cannot be exploited remotely or by anonymous network attackers. The integrity impact is high (VI:L in scope of memory, VA:H for availability) while confidentiality is unaffected (VC:N), making this primarily a sabotage or denial-of-service vector rather than data theft. EPSS score and exploitation probability data are not provided, limiting quantitative risk modeling. The 'Denial Of Service' tag combined with high availability impact suggests permanent hardware damage or memory module bricking is the primary threat. CWE-276 (Incorrect Default Permissions) is a well-understood privilege-escalation class with proven real-world impact in firmware contexts. The lack of POC or KEV listing indicates either early disclosure or limited real-world attention, but the technical simplicity of PMIC interface abuse and the specific nature of default misconfiguration suggests this is a realistic attack if an insider, disgruntled employee, or physical-access attacker gains local system access. Risk is moderate-to-high in high-security environments (data centers, supply chain) where insider threats are material; lower in consumer environments where local access itself is the primary control.

A disgruntled employee with standard user access to an enterprise workstation or server uses local privilege escalation to interact with the unprotected PMIC interface via bootloader firmware, sending crafted commands to corrupt DDR5 memory module configuration or disable power delivery. The memory module becomes unresponsive, triggering kernel panic and system crash, then fails to re-initialize on reboot, resulting in permanent system downtime. Alternatively, an attacker with physical access to a system (such as a shipping/supply chain worker) boots the system into recovery mode or BIOS, directly manipulates the PMIC configuration, and powers down the system before the corruption is detected.