CVE-2026-71967 OP-TEE CVE debrief

Who should care

Defenders of systems using OP-TEE OS with CFG_WIDEVINE_PTA enabled, especially those with exposure to Normal World clients, should assess their vulnerability and apply the patch or mitigations as necessary.

Why it matters

CVE-2026-71967 is a medium-severity vulnerability in OP-TEE OS that allows Normal World clients to cause a denial of service when CFG_WIDEVINE_PTA is enabled. Defenders of systems using OP-TEE OS with this configuration should verify their exposure and apply the patch or necessary mitigations.

• Denial of service in the trusted execution environment
• Potential disruption of critical services relying on OP-TEE OS
• Need for verification of affected versions and exposure
• Priority for patching or mitigating the vulnerability

Technical summary

The vulnerability exists in the Widevine pseudo-TA open_session handler in OP-TEE OS through 4.10.0. When CFG_WIDEVINE_PTA is enabled, Normal World clients can trigger a denial of service by opening a session directly on the Widevine PTA. This leads to an unconditional dereference of a NULL calling session pointer via is_user_ta_ctx(), causing the TEE to fault at S-EL1 and crash the trusted execution environment.

Defensive priority

Medium priority for systems using OP-TEE OS with CFG_WIDEVINE_PTA enabled, especially those with exposure to Normal World clients.

Recommended defensive actions

• Review and apply the patch from commit 0aadfc2
• Verify if CFG_WIDEVINE_PTA is enabled in your OP-TEE OS configuration
• Restrict access to the Widevine PTA to trusted clients only
• Monitor for unusual activity in the trusted execution environment
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed.
• Track exceptions, retest remediated assets, and close the item only after evidence is documented.

Evidence notes

The CVE record and NVD entry provide details on the vulnerability. However, the scope of affected versions and potential impact requires further verification from official sources. Defenders should verify if CFG_WIDEVINE_PTA is enabled in their OP-TEE OS configuration and review the patch from commit 0aadfc2. They should also restrict access to the Widevine PTA to trusted clients only and monitor for unusual activity in the trusted execution environment.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.