CVE-2025-58771: AMI APTIO V BIOS Buffer Overflow Vulnerability

CVE-2025-58771 is a buffer overflow flaw in AMI APTIO V BIOS caused by integer overflow or wraparound via local access. Successful exploitation enables arbitrary code execution and memory corruption. This article covers technical details, affected versions, impact assessment, and mitigation strategies.

CVE-2025-58771 Overview

CVE-2025-58771 is an integer overflow vulnerability [CWE-190] in AMI APTIOV BIOS firmware. An authenticated local attacker with high privileges can trigger an integer overflow or wraparound condition during BIOS operations. Successful exploitation leads to buffer overflows, memory corruption, and arbitrary code execution within the firmware context. The flaw impacts confidentiality, integrity, and availability of affected systems.

Because the vulnerability resides in BIOS firmware, successful exploitation can persist across operating system reinstallation and operate below the visibility of traditional endpoint protection. AMI published advisory SA-2026002 describing the issue.

Critical Impact
Local exploitation of the integer overflow can corrupt BIOS memory and enable arbitrary code execution at firmware privilege level, undermining platform integrity and secure boot assurances.

Affected Products

AMI APTIOV BIOS firmware (see AMI advisory SA-2026002 for affected versions)
OEM platforms shipping AMI APTIOV BIOS
Server and workstation firmware built on APTIOV reference code

Discovery Timeline

2026-10-13 - CVE-2025-58771 published to NVD
2026-10-13 - Last updated in NVD database

Technical Details for CVE-2025-58771

Vulnerability Analysis

The vulnerability is classified as an integer overflow or wraparound [CWE-190] in AMI APTIOV BIOS. BIOS code performs arithmetic on untrusted or attacker-influenced size or length values without bounds validation. When the computed value exceeds the storage width of the integer type, it wraps to a small or negative value.

Subsequent allocation and copy operations trust the wrapped result. The firmware then writes attacker-controlled data past the intended buffer boundary, corrupting adjacent memory structures. Because BIOS runs with the highest hardware privilege, memory corruption translates directly into arbitrary code execution in the pre-boot or System Management environment.

Firmware-level code execution can tamper with the boot chain, disable security features such as Secure Boot, and install persistent implants invisible to operating-system defenses.

Root Cause

The root cause is missing or insufficient validation of integer values used in size calculations within APTIOV BIOS routines. Arithmetic operations on these values produce wraparound results that bypass later length checks and feed malformed sizes into memory operations.

Attack Vector

Exploitation requires local access and high privileges on the target system. An attacker with administrative control of the operating system can reach the vulnerable BIOS interfaces through firmware communication channels such as SMI handlers, UEFI runtime services, or variable services. The attack complexity is high and no user interaction is needed. Refer to the AMI Security Advisory SA-2026002 for interface-specific details.

Detection Methods for CVE-2025-58771

Indicators of Compromise

Unexpected changes to UEFI variables, Boot Order entries, or Secure Boot configuration state.
Firmware measurement mismatches reported by TPM PCR values during remote attestation.
BIOS version strings or capsule hashes that do not match the vendor-signed baseline.
System Management Mode activity or SMI rates that deviate from the established hardware baseline.

Detection Strategies

Compare firmware images against vendor-provided hashes using tools such as CHIPSEC or vendor firmware verification utilities.
Enable and monitor TPM-backed measured boot and remote attestation to detect unauthorized firmware changes.
Audit administrative processes that invoke firmware update utilities or write to BIOS interfaces outside maintenance windows.

Monitoring Recommendations

Centralize firmware version inventory and alert on unapproved BIOS version transitions.
Collect Windows and Linux UEFI variable access logs where available and forward to a SIEM for correlation.
Monitor privileged local account activity on servers for unexpected firmware tooling execution.

How to Mitigate CVE-2025-58771

Immediate Actions Required

Apply the BIOS updates distributed by AMI and downstream OEMs that reference AMI Security Advisory SA-2026002.
Restrict local administrative access on affected systems to reduce the population of accounts able to reach vulnerable BIOS interfaces.
Enforce Secure Boot and enable TPM-based measured boot to detect post-exploitation firmware tampering.
Validate firmware integrity on critical systems before and after patch deployment using vendor hashes.

Patch Information

AMI has published advisory SA-2026002 describing the vulnerability and corresponding fixes. Platform owners must obtain BIOS updates from the system OEM that integrates the APTIOV reference code, since OEMs ship firmware tailored to specific hardware. Review the AMI Security Advisory SA-2026002 for the authoritative version information and coordinate with hardware vendors for distribution packages.

Workarounds

Limit the number of accounts with local administrator or root privileges on affected systems until firmware updates are deployed.
Disable unused firmware update paths and require signed capsule updates where the platform supports this control.
Apply vendor-recommended BIOS password protection to prevent unauthorized firmware configuration changes.

bash

# Example: verify UEFI Secure Boot state on Linux prior to and after patching
mokutil --sb-state

# Example: inventory BIOS version on Linux hosts for fleet comparison
dmidecode -s bios-version && dmidecode -s bios-release-date