CVE-2026-53763 in OP-TEE
Summary
by MITRE • 07/06/2026
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.
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Analysis
by VulDB Data Team • 07/06/2026
The vulnerability identified in OP-TEE represents a critical security flaw within the Trusted Execution Environment's cryptographic implementation that directly impacts the integrity and authenticity guarantees of encrypted communications. This issue affects versions 3.0.0 through 4.10.0 of the OP-TEE software stack, which operates as a companion to non-secure Linux kernels running on Arm Cortex-A processors utilizing TrustZone technology. The flaw specifically manifests in the AES-GCM (Advanced Encryption Standard - Galois/Counter Mode) implementation where 32-bit integer overflows occur during authentication tag computation.
The technical nature of this vulnerability stems from improper handling of bit-length calculations within the cryptographic processing pipeline. When processing data exceeding 512 megabytes of payload or Additional Authenticated Data, the system experiences integer overflow conditions that result in incorrect bit-length values being used for authentication tag generation. This overflow condition fundamentally compromises the cryptographic integrity of the encryption scheme, as the authentication mechanism fails to properly validate the encrypted data's authenticity and integrity.
The operational impact of this vulnerability extends beyond simple data corruption, creating potential attack vectors that could allow adversaries to manipulate encrypted communications without detection. Since OP-TEE serves as a TEE component protecting sensitive operations and data processing, this flaw undermines the core security guarantees that TrustZone technology is designed to provide. The vulnerability affects systems where cryptographic operations are performed in a secure environment but where the integrity protection mechanisms themselves become compromised due to the integer overflow issue.
From a cybersecurity perspective, this vulnerability aligns with CWE-191, which describes "Integer Underflow (Wrap or Wraparound)" and relates to the broader category of integer overflow conditions that can lead to security vulnerabilities. The flaw's impact on authentication tag computation directly connects to ATT&CK technique T1552.006, which covers "Unsecured Credentials" and represents how compromised cryptographic integrity can lead to credential exposure or unauthorized access. The vulnerability essentially creates a situation where attackers could potentially forge authentication tags for large data payloads, bypassing the security mechanisms that should protect against such manipulations.
The patch implemented in version 4.11.0 addresses the root cause by correcting the integer overflow conditions in the AES-GCM implementation, ensuring that bit-length calculations maintain proper boundaries even when processing large amounts of data. Organizations using OP-TEE must upgrade to version 4.11.0 or later to remediate this vulnerability, as no known workarounds exist that can effectively mitigate the risk without modifying the core cryptographic implementation. The absence of workarounds highlights the fundamental nature of the flaw within the cryptographic processing pipeline rather than a configuration issue that could be addressed through operational changes.
This vulnerability demonstrates the critical importance of proper integer handling in cryptographic implementations, where seemingly minor overflow conditions can lead to catastrophic security failures. The impact is particularly severe given that OP-TEE operates in environments where it protects sensitive data and operations from both external attackers and potentially malicious code running in the non-secure world, making any compromise of its cryptographic integrity a significant threat to overall system security.