CVE-2026-40257

OP-TEE has SHA-3 accelerated finalize heap overflow

MEDIUM
5.5
CVSS Score
Published: July 6, 2026 at 04:26 PM UTC
Updated: October 25, 2026 at 08:10 PM UTC
2 products affected across 2 vendorsOp TeeOP-TEE

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Severity
MEDIUM5.5
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

3.21.0 ≤ v ≤ 4.10.0
Affected range stops below 4.11.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (1)

x_refsource_CONFIRMMitigationPatchVendor Advisory
Source: cverecord
https://github.com/OP-TEE/optee_os/security/advisories/GHSA-75x4-j8p9-55qv

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.5MEDIUMGitHub_M
Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-787

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