OP‑TEE, a Trusted Execution Environment that runs alongside a non‑secure Linux kernel on ARM Cortex‑A cores via TrustZone, suffers a 32‑bit integer overflow in its AES‑GCM implementation. Starting in version 3.0.0 and prior to the release 4.11.0, the overflow corrupts the authentication tag’s bit‑length calculation whenever the payload or Additional Authenticated Data exceeds 512 MB. This flaw breaks the integrity guarantee of AES‑GCM, allowing an attacker who can influence data processed by the TEE to modify information without detection. It is classified as a CWE‑190 integer overflow. Based on the description, it is inferred that the vulnerability primarily affects integrity and could be exploited by an entity that can control the payload or AAD processed within the TEE.

All devices running OP‑TEE OS versions from 3.0.0 through 4.10.x are affected. The flaw was identified in the core AES‑GCM implementation and was addressed in release 4.11.0. Operators of ARM Cortex‑A based platforms that rely on the TrustZone TEE should examine the exact TEE build in use and verify the version number before applying further actions.

The CVSS score of 3.8 indicates a moderate severity. EPSS < 1% and the vulnerability is not listed in CISA’s KEV catalog, suggesting limited publicly known exploitation attempts. Based on the description, it is inferred that the likely attack vector is internal to a system component that performs large AES‑GCM operations within the trusted environment; an attacker would need to supply or influence data processed by the TEE to exceed the 512‑MB boundary. Given the absence of external exposure, the current risk is moderate but it is advisable to mitigate promptly as no workaround exists.