CVE-2025-23134

ALSA: timer: Don't take register_mutex with copy_from/to_user()

Published Apr 16, 2025 CVSS 3.1 · 5.5 Medium EPSS < 1% KEV · Not listed
Description
In the Linux kernel, the following vulnerability has been resolved:

ALSA: timer: Don't take register_mutex with copy_from/to_user()

The infamous mmap_lock taken in copy_from/to_user() can be often
problematic when it's called inside another mutex, as they might lead
to deadlocks.

In the case of ALSA timer code, the bad pattern is with
guard(mutex)(&register_mutex) that covers copy_from/to_user() -- which
was mistakenly introduced at converting to guard(), and it had been
carefully worked around in the past.

This patch fixes those pieces simply by moving copy_from/to_user() out
of the register mutex lock again.

Analysis

No analysis available yet

Remediation

No remediation available yet

Tracking

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Advisories

Source ID Title
EUVD EUVD EUVD-2025-11166 In the Linux kernel, the following vulnerability has been resolved: ALSA: timer: Don't take register_mutex with copy_from/to_user() The infamous mmap_lock taken in copy_from/to_user() can be often problematic when it's called inside another mutex, as they might lead to deadlocks. In the case of ALSA timer code, the bad pattern is with guard(mutex)(&register_mutex) that covers copy_from/to_user() -- which was mistakenly introduced at converting to guard(), and it had been carefully worked around in the past. This patch fixes those pieces simply by moving copy_from/to_user() out of the register mutex lock again.
Ubuntu USN Ubuntu USN USN-7594-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7594-2 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-7594-3 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7605-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7605-2 Linux kernel (Low Latency) vulnerabilities
Ubuntu USN Ubuntu USN USN-7606-1 Linux kernel (OEM) vulnerabilities
Ubuntu USN Ubuntu USN USN-7628-1 Linux kernel (Azure) vulnerabilities
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Weaknesses CWE-833
Type Values Removed Values Added
First Time appeared Linux
Linux linux Kernel
Weaknesses CWE-667
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: ALSA: timer: Don't take register_mutex with copy_from/to_user() The infamous mmap_lock taken in copy_from/to_user() can be often problematic when it's called inside another mutex, as they might lead to deadlocks. In the case of ALSA timer code, the bad pattern is with guard(mutex)(&register_mutex) that covers copy_from/to_user() -- which was mistakenly introduced at converting to guard(), and it had been carefully worked around in the past. This patch fixes those pieces simply by moving copy_from/to_user() out of the register mutex lock again.
Title ALSA: timer: Don't take register_mutex with copy_from/to_user()
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
May 11, 2026, 9:13 PM
Reserved
Jan 11, 2025, 2:28 PM
Status
Modified
Published
Apr 16, 2025, 3:16 PM
Modified
Jun 17, 2026, 8:52 AM
Severity
Moderate
Public date
Apr 16, 2025, 12:00 AM