CVE-2025-48507: Trusted Firmware Privilege Escalation

CVE-2025-48507 Overview

CVE-2025-48507 is a firmware vulnerability in Trusted Firmware-A (TF-A) where the security state of the calling processor is not validated. Non-secure processors can invoke privileged services intended only for secure-world callers. Successful exploitation grants access to secure memory regions, cryptographic operations, and subsystem power controls within the System-on-Chip (SoC). AMD documented the issue in AMD Security Bulletin #8017. The flaw is tracked under [CWE-1284] (Improper Validation of Specified Quantity in Input) and requires local access with low privileges to exploit.

Critical Impact
A non-secure processor can bypass the ARM TrustZone boundary, read or modify secure memory, invoke cryptographic primitives, and power subsystems on or off across the SoC.

Affected Products

AMD SoC platforms shipping Trusted Firmware-A implementations referenced in AMD Security Bulletin #8017
Firmware images derived from affected TF-A builds
Downstream products embedding vulnerable TF-A code

Discovery Timeline

2025-11-23 - CVE-2025-48507 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-48507

Vulnerability Analysis

Trusted Firmware-A implements Secure Monitor Call (SMC) handlers that execute at Exception Level 3 (EL3) on ARM-based SoCs. These handlers arbitrate access to secure services including secure memory, crypto engines, and power management. The vulnerability arises because the SMC dispatch logic does not consult the caller's Non-Secure (NS) bit to determine whether the request originated from the secure or non-secure world. Any processor context that can issue an SMC reaches the privileged service path.

The result is a broken trust boundary. Software running in the normal world, including operating system kernels or drivers, can invoke operations that should be reserved for the secure world. Consequences include disclosure of secure memory content, misuse of cryptographic keys held in secure storage, and denial of service by toggling SoC subsystems.

Root Cause

The root cause is missing validation of the caller's security state within TF-A SMC handlers. Standard practice requires reading the SCR_EL3.NS bit or equivalent security-state indicator before servicing a secure-world-only request. The affected code paths omit this check, mapping to [CWE-1284].

Attack Vector

Exploitation requires local execution on the SoC with low privileges and some user interaction, per the published CVSS 4.0 vector. An attacker with code execution in the non-secure world issues crafted SMCs to reach privileged services. No verified public proof-of-concept code is available at this time. Refer to the AMD Security Bulletin #8017 for vendor technical details.

Detection Methods for CVE-2025-48507

Indicators of Compromise

Unexpected SMC invocations from non-secure-world kernel modules or drivers targeting secure services
Unauthorized reads or writes to memory ranges designated as secure in the SoC memory map
Anomalous toggling of SoC subsystem power states outside of documented platform firmware workflows

Detection Strategies

Audit firmware version strings on all affected AMD SoC platforms against the fixed builds listed in AMD Security Bulletin #8017
Instrument TF-A builds with logging on SMC entry to capture caller security state where feasible in lab environments
Correlate kernel-level driver activity with unusual privileged firmware call patterns

Monitoring Recommendations

Track firmware and BIOS/UEFI update deployment status across the device fleet
Alert on non-secure world processes that load kernel drivers issuing SMC instructions
Include TF-A version metadata in asset inventory to identify unpatched systems quickly

How to Mitigate CVE-2025-48507

Immediate Actions Required

Apply the firmware update published in AMD Security Bulletin #8017 as soon as it is available for your platform
Restrict local access to affected systems and enforce least-privilege on user accounts able to load kernel modules
Verify Secure Boot and firmware integrity checks are enabled to prevent tampering with the updated TF-A image

Patch Information

AMD provides remediation guidance in AMD Security Bulletin #8017. Platform vendors integrate updated Trusted Firmware-A builds into BIOS or firmware releases. Consult the OEM or platform integrator for the specific firmware version that includes the fix for your product family.

Workarounds

Limit which non-secure-world software can execute privileged instructions by hardening kernel driver signing policies
Reduce local attack surface by disabling unused local interfaces and enforcing multi-factor authentication for privileged local logons
Where firmware updates are pending, isolate affected devices from untrusted workloads

bash

# Example: verify installed firmware version on Linux to confirm patch status
sudo dmidecode -s bios-version
sudo dmidecode -s bios-release-date
# Compare output against the fixed firmware version listed in AMD-SB-8017