CVE-2025-21923

Kernel code execution via rescheduled detach work

Published Apr 1, 2025 · Updated Aug 5, 2026

Use-after-free in the Linux hid-steam driver allows local users to execute arbitrary kernel code by detaching a crafted UHID device. The detach path cancels unregister_work before cleaning up client_hdev, whose close callback queues the work again so it later dereferences freed steam_device and hid_device objects. Access to /dev/uhid and the resulting /dev/hidraw node is required; exploitation can disclose or alter kernel memory or crash the system.

CVSS severity7.8
High
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in the Linux hid-steam driver allows local users to execute arbitrary kernel code by detaching a crafted UHID device. The detach path cancels unregister_work before cleaning up client_hdev, whose close callback queues the work again so it later dereferences freed steam_device and hid_device objects. Access to /dev/uhid and the resulting /dev/hidraw node is required; exploitation can disclose or alter kernel memory or crash the system.

The record

CVE
CVE-2025-21923
Published
Apr 1, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 1, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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=053fa3888d2a957f4db26c05e503f4c6b9570a30 <ea3f18d2f02629653b7bfe42607737ccd1343e54
  2. Affected versionversion=3e38cbbfa0a128a9d64773240a9eb3bc7bae3b1a <a899adf7063c6745aaff1ec869f3c7f6329ed0a1
  3. Affected versionversion=6.12.16 <6.12.19
  4. Affected versionversion=6.13.4 <6.13.7
  5. Affected versionversion=6.6.79 <6.6.83
  6. Affected versionversion=79504249d7e27cad4a3eeb9afc6386e418728ce0 <e53fc232a65f7488ab75d03a5b95f06aaada7262
  7. Affected versionversion=e1147961b2145fa61c3078a4a797d9576cde91ab <026714ec7546de741826324a6a1914c91024d06c

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=053fa3888d2a957f4db26c05e503f4c6b9570a30 <ea3f18d2f02629653b7bfe42607737ccd1343e54; version=3e38cbbfa0a128a9d64773240a9eb3bc7bae3b1a <a899adf7063c6745aaff1ec869f3c7f6329ed0a1; version=6.12.16 <6.12.19; version=6.13.4 <6.13.7; version=6.6.79 <6.6.83; version=79504249d7e27cad4a3eeb9afc6386e418728ce0 <e53fc232a65f7488ab75d03a5b95f06aaada7262; version=e1147961b2145fa61c3078a4a797d9576cde91ab <026714ec7546de741826324a6a1914c91024d06c

Published CVSS scores

7.8LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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

T1068Exploitation for Privilege Escalation

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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