CVE-2025-23134

System hang via ALSA timer lock inversion

Published Apr 16, 2025 · Updated May 11, 2026

Improper locking in the ALSA timer code in Linux allows local users to hang the system through concurrent timer operations. The timer ioctl paths hold register_mutex while copy_from_user or copy_to_user can acquire mmap_lock, creating a lock-order deadlock. Reachability requires low-privileged local access to ALSA timer operations; the documented impact is availability loss without data disclosure or modification.

CVSS severity5.5
Medium
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper locking in the ALSA timer code in Linux allows local users to hang the system through concurrent timer operations. The timer ioctl paths hold register_mutex while copy_from_user or copy_to_user can acquire mmap_lock, creating a lock-order deadlock. Reachability requires low-privileged local access to ALSA timer operations; the documented impact is availability loss without data disclosure or modification.

The record

CVE
CVE-2025-23134
Published
Apr 16, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-667, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 16, 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=3923de04c81733b30b8ed667569632272fdfed9a <15291b561d8cc835a2eea76b394070cf8e072771
  2. Affected versionversion=3923de04c81733b30b8ed667569632272fdfed9a <296f7a9e15aab276db11206cbc1e2ae1215d7862
  3. Affected versionversion=3923de04c81733b30b8ed667569632272fdfed9a <3424c8f53bc63c87712a7fc22dc13d0cc85fb0d6
  4. Affected versionversion=3923de04c81733b30b8ed667569632272fdfed9a <b074f47e55df93832bbbca1b524c501e6fea1c0d
  5. Affected versionversion=6.9

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=3923de04c81733b30b8ed667569632272fdfed9a <15291b561d8cc835a2eea76b394070cf8e072771; version=3923de04c81733b30b8ed667569632272fdfed9a <296f7a9e15aab276db11206cbc1e2ae1215d7862; version=3923de04c81733b30b8ed667569632272fdfed9a <3424c8f53bc63c87712a7fc22dc13d0cc85fb0d6; version=3923de04c81733b30b8ed667569632272fdfed9a <b074f47e55df93832bbbca1b524c501e6fea1c0d; version=6.9

Published CVSS scores

5.5CISA-ADPCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
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.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-667Improper Locking
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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