A critical stack-based buffer overflow in TrustedFirmware-M allows unauthenticated attackers to manipulate system memory during the firmware upgrade process.

This vulnerability occurs due to a lack of length validation within the Firmware Upgrade module's Type-Length-Value structure processing. An unauthenticated attacker can supply a crafted firmware upgrade image containing a malicious TLV entry to trigger an out-of-bounds write on the stack.

Successful exploitation of this vulnerability could lead to arbitrary code execution or system instability by corrupting critical stack data. Given the CVSS score of 8.6, this flaw represents a significant risk to the integrity and availability of embedded systems relying on TrustedFirmware-M, potentially allowing for full compromise of the device firmware.

Immediate Action: Update TrustedFirmware-M to version 2.1.3 or 2.2.1 or later to implement proper TLV length validation.

Proactive Monitoring: Monitor firmware update logs for anomalous length parameters or failed upgrade attempts that may indicate exploitation efforts.

Compensating Controls: Restrict access to firmware upgrade interfaces and ensure that only cryptographically signed and verified images are processed by the bootloader.

Public Exploit Available: No (exploit_available: unknown)

The severity of this stack-based buffer overflow necessitates prompt attention, as it undermines the fundamental security of the firmware update mechanism. Administrators must verify their current firmware version and apply the recommended updates to prevent potential system compromise.