CVE-2025-21871

System hang via unkillable supplicant response wait

Published Mar 27, 2025 · Updated May 11, 2026

Denial of service in the OP-TEE driver in affected Linux kernel releases allows local users to hang the system during an RPC call. The supplicant request path repeats an uninterruptible response wait after the user-space daemon stalls or exits, leaving the client task permanently unkillable. Exploitation requires local low-privileged access and an OP-TEE RPC in flight; the resulting system hang can require a hard power cycle.

CVSS severity5.5
Medium
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in the OP-TEE driver in affected Linux kernel releases allows local users to hang the system during an RPC call. The supplicant request path repeats an uninterruptible response wait after the user-space daemon stalls or exits, leaving the client task permanently unkillable. Exploitation requires local low-privileged access and an OP-TEE RPC in flight; the resulting system hang can require a hard power cycle.

The record

CVE
CVE-2025-21871
Published
Mar 27, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-835, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 27, 2025CVE publishedPublication date reported by the CVE source.
  2. May 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.12
  2. Affected versionversion=4fb0a5eb364d239722e745c02aef0dbd4e0f1ad2 <0180cf0373f84fff61b16f8c062553a13dd7cfca
  3. Affected versionversion=4fb0a5eb364d239722e745c02aef0dbd4e0f1ad2 <21234efe2a8474a6d2d01ea9573319de7858ce44
  4. Affected versionversion=4fb0a5eb364d239722e745c02aef0dbd4e0f1ad2 <3eb4911364c764572e9db4ab900a57689a54e8ce
  5. Affected versionversion=4fb0a5eb364d239722e745c02aef0dbd4e0f1ad2 <70b0d6b0a199c5a3ee6c72f5e61681ed6f759612
  6. Affected versionversion=4fb0a5eb364d239722e745c02aef0dbd4e0f1ad2 <c0a9a948159153be145f9471435695373904ee6d
  7. Affected versionversion=4fb0a5eb364d239722e745c02aef0dbd4e0f1ad2 <d61cc1a435e6894bfb0dd3370c6f765d2d12825d
  8. Affected versionversion=4fb0a5eb364d239722e745c02aef0dbd4e0f1ad2 <ec18520f5edc20a00c34a8c9fdd6507c355e880f
  9. Affected versionversion=4fb0a5eb364d239722e745c02aef0dbd4e0f1ad2 <fd9d2d6124c293e40797a080adf8a9c237efd8b8

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.12; version=4fb0a5eb364d239722e745c02aef0dbd4e0f1ad2 <0180cf0373f84fff61b16f8c062553a13dd7cfca; version=4fb0a5eb364d239722e745c02aef0dbd4e0f1ad2 <21234efe2a8474a6d2d01ea9573319de7858ce44; version=4fb0a5eb364d239722e745c02aef0dbd4e0f1ad2 <3eb4911364c764572e9db4ab900a57689a54e8ce; version=4fb0a5eb364d239722e745c02aef0dbd4e0f1ad2 <70b0d6b0a199c5a3ee6c72f5e61681ed6f759612; version=4fb0a5eb364d239722e745c02aef0dbd4e0f1ad2 <c0a9a948159153be145f9471435695373904ee6d; version=4fb0a5eb364d239722e745c02aef0dbd4e0f1ad2 <d61cc1a435e6894bfb0dd3370c6f765d2d12825d; version=4fb0a5eb364d239722e745c02aef0dbd4e0f1ad2 <ec18520f5edc20a00c34a8c9fdd6507c355e880f; version=4fb0a5eb364d239722e745c02aef0dbd4e0f1ad2 <fd9d2d6124c293e40797a080adf8a9c237efd8b8

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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