CVE-2026-40257: CWE-787: Out-of-bounds Write in OP-TEE optee_os
An out-of-bounds write vulnerability exists in OP-TEE's ARM Crypto Extensions accelerated SHA-3 implementation in versions starting from 3.21.0 up to but not including 4.11.0. This off-by-one error causes a heap overflow that corrupts TEE kernel memory following the hash state when built with CFG_CRYPTO_WITH_CE82=y. Version 4.11.0 includes a patch. A workaround is to disable the SHA3 Crypto Extensions by setting CFG_CRYPTO_WITH_CE82=n.
AI Analysis
Technical Summary
OP-TEE, a Trusted Execution Environment for ARM Cortex-A cores using TrustZone, contains an off-by-one error in the ARM Crypto Extensions accelerated SHA-3 implementation affecting versions >=3.21.0 and <4.11.0. This vulnerability leads to a massive heap overflow corrupting all TEE kernel memory following the hash state when the build configuration CFG_CRYPTO_WITH_CE82 is enabled (ARMv8.2+ with SHA3 Crypto Extensions). The issue is fixed in version 4.11.0. A workaround is to disable the SHA3 Crypto Extensions by setting CFG_CRYPTO_WITH_CE82 to 'n'.
Potential Impact
The vulnerability causes a heap overflow that corrupts the Trusted Execution Environment kernel memory following the hash state. This results in a denial of service or potential instability of the TEE kernel. The CVSS score is 5.5 (medium severity), with no confidentiality or integrity impact but high impact on availability. There are no known exploits in the wild.
Mitigation Recommendations
Version 4.11.0 of OP-TEE contains a patch that fixes this vulnerability. Users should upgrade to version 4.11.0 or later. As a workaround, disabling the SHA3 Crypto Extensions by setting CFG_CRYPTO_WITH_CE82=n in the build configuration will mitigate the issue. Patch status is not explicitly confirmed beyond the mention of version 4.11.0 containing a patch, so users should verify with the vendor advisory for the latest remediation guidance.
CVE-2026-40257: CWE-787: Out-of-bounds Write in OP-TEE optee_os
Description
An out-of-bounds write vulnerability exists in OP-TEE's ARM Crypto Extensions accelerated SHA-3 implementation in versions starting from 3.21.0 up to but not including 4.11.0. This off-by-one error causes a heap overflow that corrupts TEE kernel memory following the hash state when built with CFG_CRYPTO_WITH_CE82=y. Version 4.11.0 includes a patch. A workaround is to disable the SHA3 Crypto Extensions by setting CFG_CRYPTO_WITH_CE82=n.
CVSS v3.1
Score 5.5medium
Affected software
pkg:github/op-tee/optee_osRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
OP-TEE, a Trusted Execution Environment for ARM Cortex-A cores using TrustZone, contains an off-by-one error in the ARM Crypto Extensions accelerated SHA-3 implementation affecting versions >=3.21.0 and <4.11.0. This vulnerability leads to a massive heap overflow corrupting all TEE kernel memory following the hash state when the build configuration CFG_CRYPTO_WITH_CE82 is enabled (ARMv8.2+ with SHA3 Crypto Extensions). The issue is fixed in version 4.11.0. A workaround is to disable the SHA3 Crypto Extensions by setting CFG_CRYPTO_WITH_CE82 to 'n'.
Potential Impact
The vulnerability causes a heap overflow that corrupts the Trusted Execution Environment kernel memory following the hash state. This results in a denial of service or potential instability of the TEE kernel. The CVSS score is 5.5 (medium severity), with no confidentiality or integrity impact but high impact on availability. There are no known exploits in the wild.
Mitigation Recommendations
Version 4.11.0 of OP-TEE contains a patch that fixes this vulnerability. Users should upgrade to version 4.11.0 or later. As a workaround, disabling the SHA3 Crypto Extensions by setting CFG_CRYPTO_WITH_CE82=n in the build configuration will mitigate the issue. Patch status is not explicitly confirmed beyond the mention of version 4.11.0 containing a patch, so users should verify with the vendor advisory for the latest remediation guidance.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-04-10T17:31:45.787Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a4bdd5a27e9c79719dab253
Added to database: 07/06/2026, 16:52:42 UTC
Last enriched: 07/06/2026, 17:07:49 UTC
Last updated: 07/06/2026, 18:48:08 UTC
Views: 7
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