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Fencer Intel
medium 5.5

CVE-2025-23134 json

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

published last yr. modified 4mo ago also EUVD-2025-11166

cvss
5.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 4%
public exploits
0
none known

Summary

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.

Patch / fix

  • Linux Linux 6.12.23, 6.13.11, 6.14.2, 6.15
  • linux Debian 14, Debian 13 6.12.25-1

debian advisories DEBIAN-CVE-2025-23134

  • linux-gcp-6.11 Ubuntu 24.04 LTS 6.11.0-1016.16~24.04.1
  • linux-hwe-6.11 Ubuntu 24.04 LTS 6.11.0-28.28~24.04.1
  • linux-oem-6.11 Ubuntu 24.04 LTS 6.11.0-1024.24
  • linux-azure-6.11 Ubuntu 24.04 LTS 6.11.0-1018.18~24.04.1
  • linux-nvidia-6.11 Ubuntu 24.04 LTS 6.11.0-1012.12
  • linux-lowlatency-hwe-6.11 Ubuntu 24.04 LTS 6.11.0-1015.16~24.04.2

ubuntu advisories UBUNTU-CVE-2025-23134

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel-rt Real Time Module 15 SP7 6.4.0-150700.7.3.1
  • kernel-syms-rt Real Time Module 15 SP7 6.4.0-150700.7.3.1
  • kernel-rt_debug Real Time Module 15 SP7 6.4.0-150700.7.3.1
  • kernel-source-rt Real Time Module 15 SP7 6.4.0-150700.7.3.1
  • kernel-azure SLE Module for Public Cloud 15 SP7 6.4.0-150700.20.3.1
  • kernel-syms-azure SLE Module for Public Cloud 15 SP7 6.4.0-150700.20.3.1
  • kernel-source-azure SLE Module for Public Cloud 15 SP7 6.4.0-150700.20.3.1
  • kernel-64kb SLE Module for Basesystem 15 SP7 6.4.0-150700.53.3.1

suse advisories SUSE-SU-2025:01972-1SUSE-SU-2025:01967-1SUSE-SU-2025:01951-1

Is CVE-2025-23134 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-23134 updated cvss 5.5

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

  • Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more Red Hat Enterprise Linux 10 kernel
    affected: no fix available “Fix deferred”
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
last yr.

Exploit prediction

0.15% chance of exploitation in the next 30 days, higher than 4% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CISA ADP 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CNA 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Linux Linux

Classification

Weakness
Technology feeds

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.