CVE-2026-41434 Overview
CVE-2026-41434 affects OP-TEE, an open-source Trusted Execution Environment (TEE) that runs alongside a non-secure Linux kernel on Arm Cortex-A processors using TrustZone technology. Versions from 3.10.0 through releases prior to 4.11.0 contain an unbounded recursion flaw in the PKCS#11 Trusted Application (TA). A local authenticated attacker can trigger the recursion and crash the PKCS#11 TA, causing a denial of service. The issue is tracked under [CWE-121] (Stack-based Buffer Overflow) and resolved in version 4.11.0. No workarounds are available according to the vendor advisory.
Critical Impact
An attacker with local access and low privileges can crash the PKCS#11 Trusted Application, disrupting cryptographic services delivered by the secure world.
Affected Products
- Trustedfirmware OP-TEE versions 3.10.0 through 4.10.x
- OP-TEE PKCS#11 Trusted Application (TA)
- Devices running OP-TEE on Arm Cortex-A cores with TrustZone
Discovery Timeline
- 2026-07-06 - CVE-2026-41434 published to NVD
- 2026-07-07 - Last updated in NVD database
Technical Details for CVE-2026-41434
Vulnerability Analysis
OP-TEE provides a secure world runtime that hosts Trusted Applications, including a PKCS#11 TA implementing the standard cryptographic token interface. The PKCS#11 TA parses attribute structures supplied by clients in the non-secure world. A code path in the TA processes nested attribute data using recursion without enforcing a bound on recursion depth. An attacker crafts input that triggers deep recursion, exhausting the TA's stack in the secure world. Stack exhaustion crashes the PKCS#11 TA, terminating cryptographic operations for all clients relying on that TA.
Root Cause
The root cause is unbounded recursion in the PKCS#11 TA's attribute handling logic. The implementation does not validate nesting depth before making recursive calls. Because TAs execute with a fixed, small stack in the secure world, a modest recursion depth is sufficient to overflow the stack. This maps to [CWE-121], stack-based buffer overflow, expressed here as stack exhaustion rather than a controlled overwrite.
Attack Vector
Exploitation requires local access to the device and the ability to invoke the PKCS#11 TA through the standard TEE client API. Any process with permission to open a session to the TA can submit crafted attribute data. No user interaction is required. The impact is limited to availability of the PKCS#11 TA. Confidentiality and integrity are not affected, and the crash does not yield code execution in the secure world.
No public proof-of-concept or exploit code is available. See the OP-TEE GitHub Security Advisory GHSA-wh38-23ff-grff for vendor technical details.
Detection Methods for CVE-2026-41434
Indicators of Compromise
- Unexpected termination or panic messages from the PKCS#11 TA in OP-TEE secure world logs
- Repeated TEEC_ERROR_TARGET_DEAD return codes from client applications invoking PKCS#11 operations
- Sudden loss of cryptographic token availability on affected devices
Detection Strategies
- Monitor OP-TEE kernel and secure world logs for TA abort messages referencing the PKCS#11 TA UUID
- Track client-side error rates on TEE Client API calls to detect surges consistent with TA crashes
- Inventory deployed OP-TEE versions across fleet devices and flag any version between 3.10.0 and 4.10.x
Monitoring Recommendations
- Forward device telemetry, including tee-supplicant and kernel ring buffer entries, to a centralized log platform
- Alert on abnormal reload frequency of the PKCS#11 TA on production devices
- Correlate local user activity with TA crash events to identify potential exploitation attempts
How to Mitigate CVE-2026-41434
Immediate Actions Required
- Upgrade OP-TEE OS to version 4.11.0 or later on all affected devices
- Rebuild and re-sign firmware images that embed the PKCS#11 TA against the patched OP-TEE source
- Restrict which local processes can open sessions to the PKCS#11 TA to trusted components only
Patch Information
The vendor released a fix in OP-TEE version 4.11.0. The patch introduces bounds on recursion within the PKCS#11 TA's attribute processing to prevent stack exhaustion. Refer to the OP-TEE GitHub Security Advisory GHSA-wh38-23ff-grff for commit references and integration guidance.
Workarounds
- No vendor-supplied workarounds are available; upgrading to OP-TEE 4.11.0 is required
- As a compensating control, limit local access to devices and enforce least privilege on clients invoking TEE services
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
