OP-TEE up to 4.10.x SHA-3 Implementation off-by-one

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.
CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
4.0$0-$5k2.38+

Summaryinfo

A vulnerability was found in OP-TEE up to 4.10.x. It has been declared as problematic. Impacted is an unknown function of the component SHA-3 Implementation. Executing a manipulation can lead to off-by-one. This vulnerability is registered as CVE-2026-40257. The attack needs to be launched locally. No exploit is available.

Detailsinfo

A vulnerability classified as problematic was found in OP-TEE up to 4.10.x. This vulnerability affects some unknown processing of the component SHA-3 Implementation. The manipulation with an unknown input leads to a off-by-one vulnerability. The CWE definition for the vulnerability is CWE-193. A product calculates or uses an incorrect maximum or minimum value that is 1 more, or 1 less, than the correct value. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

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`.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-40257 since 04/10/2026. The exploitation appears to be easy. The attack needs to be approached locally. The exploitation requires an enhanced level of successful authentication. There are neither technical details nor an exploit publicly available.

Upgrading to version 4.11.0 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-41891). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.2
VulDB Meta Temp Score: 4.0

VulDB Base Score: 4.2
VulDB Temp Score: 4.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Off-by-one
CWE: CWE-193 / CWE-189
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

0-DayUnlockUnlockUnlockUnlock
TodayUnlockUnlockUnlockUnlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Upgrade: OP-TEE 4.11.0

Timelineinfo

04/10/2026 CVE reserved
07/06/2026 +87 days Advisory disclosed
07/06/2026 +0 days VulDB entry created
07/06/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-40257 (🔒)
GCVE (CVE): GCVE-0-2026-40257
GCVE (VulDB): GCVE-100-376480
EUVD: 🔒

Entryinfo

Created: 07/06/2026 18:54
Updated: 07/06/2026 21:27
Changes: 07/06/2026 18:54 (52), 07/06/2026 21:27 (1)
Complete: 🔍
Cache ID: 216::103

VulDB is the best source for vulnerability data and more expert information about this specific topic.

Discussion

No comments yet. Languages: en.

Please log in to comment.

◂ PreviousOverviewNext ▸

Want to stay up to date on a daily basis?

Enable the mail alert feature now!