CVE-2025-21871: Linux kernel · tee: optee: Fix supplicant wait loop OP-TEE supplicant is a user-space daemon and it's
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · fixed in 5.4.0-1146.156~18.04.1 : update Linux kernel when convenient.
Data as of 30 Oct 2026, 23:12 UTC
- Patch
- Available – fixed in 5.4.0-1146.156~18.04.1, 5.4.0-1151.158~18.04.1, 5.4.0-1149.158~18.04.1 +83
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 27 Mar 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Patches and advisories
- ubuntu.com/security/notices/USN-7510-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7510-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7511-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7511-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7512-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7516-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7516-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7517-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7518-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7521-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7510-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7510-4 (opens in a new tab)
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 24.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azure-6.11pkg:deb/ubuntu/linux-azure-6.11?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azure-nvidiapkg:deb/ubuntu/linux-azure-nvidia?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix is available and included in Linux kernel versions 5.4.0-1146.156~18.04.1, 5.4.0-1151.158~18.04.1, 5.4.0-1149.158~18.04.1, 5.4.0-216.236~18.04.1, 5.4.0-1092.97~18.04.1, 5.4.0-1144.154~18.04.1, 5.4.0-1129.142~18.04.1, 5.4.0-216.236, 5.4.0-1146.156, and 5.15.0-1084.91~20.04.1. Users should apply the relevant Linux kernel updates and reboot systems to resolve the issue. No additional mitigations are required beyond applying the official patches.
Description
CVE-2025-21871 is a vulnerability in the Linux kernel's OP-TEE supplicant, a user-space daemon that handles RPC calls for the Trusted Execution Environment. The flaw allows the supplicant to hang, crash, or be killed during processing, causing the client application to wait indefinitely in an unkillable state. This can lead to system hang-ups, especially during reboot or shutdown, requiring a hard power cycle to recover. The issue has been fixed in updated Linux kernel versions.
References
- ubuntu.com/security/CVE-2025-21871 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-21871 (opens in a new tab)
- git.kernel.org/linus/70b0d6b0a199c5a3ee6c72f5e61681ed6f759612 (opens in a new tab)
- git.kernel.org/stable/c/0180cf0373f84fff61b16f8c062553a13dd7cfca (opens in a new tab)
- git.kernel.org/stable/c/21234efe2a8474a6d2d01ea9573319de7858ce44 (opens in a new tab)
- git.kernel.org/stable/c/3eb4911364c764572e9db4ab900a57689a54e8ce (opens in a new tab)
- git.kernel.org/stable/c/70b0d6b0a199c5a3ee6c72f5e61681ed6f759612 (opens in a new tab)
- git.kernel.org/stable/c/c0a9a948159153be145f9471435695373904ee6d (opens in a new tab)
- git.kernel.org/stable/c/d61cc1a435e6894bfb0dd3370c6f765d2d12825d (opens in a new tab)
- git.kernel.org/stable/c/ec18520f5edc20a00c34a8c9fdd6507c355e880f (opens in a new tab)
- git.kernel.org/stable/c/fd9d2d6124c293e40797a080adf8a9c237efd8b8 (opens in a new tab)
- ubuntu.com/security/notices/USN-7510-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7510-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7511-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7511-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7512-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7516-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7516-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7517-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7518-1 (opens in a new tab)