CVE-2026-41516: CWE-208: Observable Timing Discrepancy in OP-TEE optee_os
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 4.5.0 and prior to version 4.11.0, the RSA PKCS#1 v1.5 decryption implementation in the Hisilicon HPRE crypto driver uses non-constant-time `memcmp()` for label hash verification and has multiple distinguishable error paths. This creates a Bleichenbacher-style padding oracle that allows an attacker to recover RSA PKCS#1 v1.5 plaintext. Version 4.11.0 contains a patch. As a workaround, disable Hisilicon HPRE RSA driver with `CFG_HISILICON_ACC_V3=n`.
AI Analysis
Technical Summary
The OP-TEE Trusted Execution Environment's Hisilicon HPRE crypto driver in versions starting at 4.5.0 and prior to 4.11.0 implements RSA PKCS#1 v1.5 decryption with a non-constant-time memcmp() function for label hash verification and multiple distinct error responses. This timing discrepancy and error path differentiation create a Bleichenbacher-style padding oracle vulnerability, enabling an attacker to recover RSA plaintext. The vulnerability is fixed in version 4.11.0. As a workaround, disabling the Hisilicon HPRE RSA driver by setting CFG_HISILICON_ACC_V3=n mitigates the issue.
Potential Impact
An attacker with local access can exploit the timing discrepancy and error path differences in the RSA PKCS#1 v1.5 decryption to recover plaintext data. The confidentiality of RSA encrypted data is impacted. There is no impact on integrity or availability. The CVSS score is low (2.5) reflecting the limited attack vector (local) and complexity (high).
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 temporary workaround, disable the Hisilicon HPRE RSA driver by setting CFG_HISILICON_ACC_V3=n in the configuration. Patch status is not explicitly confirmed beyond the mention of version 4.11.0 containing a fix; verify with the vendor advisory for the latest remediation guidance.
CVE-2026-41516: CWE-208: Observable Timing Discrepancy in OP-TEE optee_os
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 4.5.0 and prior to version 4.11.0, the RSA PKCS#1 v1.5 decryption implementation in the Hisilicon HPRE crypto driver uses non-constant-time `memcmp()` for label hash verification and has multiple distinguishable error paths. This creates a Bleichenbacher-style padding oracle that allows an attacker to recover RSA PKCS#1 v1.5 plaintext. Version 4.11.0 contains a patch. As a workaround, disable Hisilicon HPRE RSA driver with `CFG_HISILICON_ACC_V3=n`.
CVSS v3.1
Score 2.5low
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
The OP-TEE Trusted Execution Environment's Hisilicon HPRE crypto driver in versions starting at 4.5.0 and prior to 4.11.0 implements RSA PKCS#1 v1.5 decryption with a non-constant-time memcmp() function for label hash verification and multiple distinct error responses. This timing discrepancy and error path differentiation create a Bleichenbacher-style padding oracle vulnerability, enabling an attacker to recover RSA plaintext. The vulnerability is fixed in version 4.11.0. As a workaround, disabling the Hisilicon HPRE RSA driver by setting CFG_HISILICON_ACC_V3=n mitigates the issue.
Potential Impact
An attacker with local access can exploit the timing discrepancy and error path differences in the RSA PKCS#1 v1.5 decryption to recover plaintext data. The confidentiality of RSA encrypted data is impacted. There is no impact on integrity or availability. The CVSS score is low (2.5) reflecting the limited attack vector (local) and complexity (high).
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 temporary workaround, disable the Hisilicon HPRE RSA driver by setting CFG_HISILICON_ACC_V3=n in the configuration. Patch status is not explicitly confirmed beyond the mention of version 4.11.0 containing a fix; verify with the vendor advisory for the latest remediation guidance.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-04-20T18:18:50.681Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a4c076827e9c7971920cb9d
Added to database: 07/06/2026, 19:52:08 UTC
Last enriched: 07/06/2026, 20:07:30 UTC
Last updated: 07/06/2026, 21:26:00 UTC
Views: 3
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