CVE-2026-53763 OP-TEE has AES-GCM 32-bit integer overflow in length counters that breaks authentication guarantee

Low 3.8 Published 6 Jul 2026 Updated 7 Jul 2026

Integer overflow in OP-TEE AES-GCM implementation breaks authentication tags for large payloads, allowing security bypass in Trusted Execution Environments.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Local or same network only
Victim action needed: Not needed
Fix: None listed

What is CVE-2026-53763?

CVE-2026-53763 is a low-severity vulnerability in OP-TEE optee_os, published on 6 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

OP-TEE is a Trusted Execution Environment (TEE) designed as companion to a non-secure Linux kernel running on Arm; Cortex-A cores using the TrustZone technology. Starting in version 3.0.0 and prior to version 4.11.0, 32-bit integer overflows in OP-TEE core's AES-GCM implementation cause the authentication tag to be computed with incorrect bit-length values after processing more than 512 megabytes of payload or Additional Authenticated Data (AAD). Version 4.11.0 contains a patch. No known workarounds are available.

Weakness: CWE-190

Which versions are affected by CVE-2026-53763?

It affects 1 product.

Products include Trustedfirmware Op-Tee.

How do I fix CVE-2026-53763?

No fix has been published for CVE-2026-53763 yet. Limit exposure of the affected software until one is available.

Is CVE-2026-53763 being exploited?

There is no known exploitation of CVE-2026-53763 in the wild and no public exploit code.

Sources

Also known as DEBIAN-CVE-2026-53763, GHSA-fcm8-vjhf-6vqh, UBUNTU-CVE-2026-53763.