Vulnerability 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 3.21.0 and prior to version 4.11.0, the ARM Crypto Extensions accelerated SHA-3 implementation has an off-by-one error that can cause a massive heap overflow that corrupts all TEE kernel memory following the hash state. This affects all platforms built with `CFG_CRYPTO_WITH_CE82=y` (ARMv8.2+ with SHA3 Crypto Extensions). Version 4.11.0 contains a patch. As a workaround, disable SHA3 Crypto Extensions with `CFG_CRYPTO_WITH_CE82=n`.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Trustedfirmware | Op-Tee | >= 3.21.0, <= 4.10.0 |
Related Weaknesses (CWE)
References
- https://github.com/OP-TEE/optee_os/security/advisories/GHSA-75x4-j8p9-55qvMitigationPatchVendor Advisory
FAQ
What is CVE-2026-40257?
CVE-2026-40257 is a vulnerability with a CVSS score of 5.5 (MEDIUM). 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 3.21.0 and prior t...
How severe is CVE-2026-40257?
CVE-2026-40257 has been rated MEDIUM with a CVSS base score of 5.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-40257?
Check the references section above for vendor advisories and patch information. Affected products include: Trustedfirmware Op-Tee.