Log in Start free

Vulnerability · Published Jul 6, 2026 · Assigned by GitHub_M

CVE-2026-40257OP-TEE has SHA-3 accelerated finalize heap overflow

Medium 5.5

In plain English

A medium-severity out-of-bounds write in optee_os from OP-TEE. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 4% of all known vulnerabilities).

Severity (CVSS 3.1)5.5Medium
Exploit odds (30 days)0.2%top 95.5% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

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 3.21.0 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`.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:13optee-osno fix listedDEBIAN-CVE-2026-40257
Ubuntu:25.10optee-osno fix listedUBUNTU-CVE-2026-40257
Ubuntu:26.04:LTSoptee-osno fix listedUBUNTU-CVE-2026-40257
Ubuntu:26.10optee-osno fix listedUBUNTU-CVE-2026-40257

Affected products (as reported)

VendorProductVersions
OP-TEE optee_os >= 3.21.0, < 4.11.0

Weakness: CWE-787 · Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

References