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Fencer Vulns
medium 5.5

CVE-2025-21672 json

afs: Fix merge preference rule failure condition

published 2025-01-31 21 mo ago modified 2026-06-17 4 mo ago also EUVD-2025-2621

cvss
5.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 3%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

afs: Fix merge preference rule failure condition

syzbot reported a lock held when returning to userspace[1]. This is because if argc is less than 0 and the function returns directly, the held inode lock is not released.

Fix this by store the error in ret and jump to done to clean up instead of returning directly.

[dh: Modified Lizhi Xu's original patch to make it honour the error code from afs_split_string()]

[1] WARNING: lock held when returning to user space! 6.13.0-rc3-syzkaller-00209-g499551201b5f #0 Not tainted ------------------------------------------------ syz-executor133/5823 is leaving the kernel with locks still held! 1 lock held by syz-executor133/5823: #0: ffff888071cffc00 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock include/linux/fs.h:818 [inline] #0: ffff888071cffc00 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: afs_proc_addr_prefs_write+0x2bb/0x14e0 fs/afs/addr_prefs.c:388

Patch / fix

  • Linux Linux 6.12.11, 6.13
  • linux Debian 14, Debian 13 6.12.11-1

debian advisories DEBIAN-CVE-2025-21672

  • linux Ubuntu 24.04 LTS 6.8.0-62.65
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1030.32
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1031.33
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1026.30
  • linux-ibm Ubuntu 24.04 LTS 6.8.0-1027.27
  • linux-azure Ubuntu 24.04 LTS 6.8.0-1030.35
  • linux-gkeop Ubuntu 24.04 LTS 6.8.0-1013.15
  • linux-raspi Ubuntu 24.04 LTS 6.8.0-1029.33

ubuntu advisories UBUNTU-CVE-2025-21672

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 RHEL 9 5.14.0-611.5.1.el9_7
  • rv RHEL 9 5.14.0-611.5.1.el9_7
  • perf RHEL 9 5.14.0-611.5.1.el9_7
  • rtla RHEL 9 5.14.0-611.5.1.el9_7
  • libperf RHEL 9 5.14.0-611.5.1.el9_7
  • kernel-rt RHEL 9 5.14.0-611.5.1.el9_7
  • kernel-64k RHEL 9 5.14.0-611.5.1.el9_7
  • kernel-core RHEL 9 5.14.0-611.5.1.el9_7

red hat advisories RHSA-2025:20518

  • kernel AlmaLinux 9 5.14.0-611.5.1.el9_7
  • rv AlmaLinux 9 5.14.0-611.5.1.el9_7
  • perf AlmaLinux 9 5.14.0-611.5.1.el9_7
  • rtla AlmaLinux 9 5.14.0-611.5.1.el9_7
  • libperf AlmaLinux 9 5.14.0-611.5.1.el9_7
  • kernel-rt AlmaLinux 9 5.14.0-611.5.1.el9_7
  • kernel-64k AlmaLinux 9 5.14.0-611.5.1.el9_7
  • kernel-core AlmaLinux 9 5.14.0-611.5.1.el9_7

almalinux advisories ALSA-2025:20518

  • kernel Rocky Linux 9 5.14.0-611.5.1.el9_7

rocky linux advisories RLSA-2025:20518

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-2025-21672 updated cvss 5.5

kernel: afs: Fix merge preference rule failure condition

  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-611.5.1.el9_7, perf 5.14.0-611.5.1.el9_7, rtla 5.14.0-611.5.1.el9_7, python3-perf 5.14.0-611.5.1.el9_7, kernel-devel-matched 5.14.0-611.5.1.el9_7, kernel-64k-devel-matched 5.14.0-611.5.1.el9_7, +7 more Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-611.5.1.el9_7, kernel-64k 5.14.0-611.5.1.el9_7, kernel-core 5.14.0-611.5.1.el9_7, kernel-tools 5.14.0-611.5.1.el9_7, kernel-modules 5.14.0-611.5.1.el9_7, kernel-64k-core 5.14.0-611.5.1.el9_7, +27 more Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-611.5.1.el9_7, kernel-debuginfo-common-s390x 5.14.0-611.5.1.el9_7, kernel-debuginfo-common-x86_64 5.14.0-611.5.1.el9_7, kernel-debuginfo-common-aarch64 5.14.0-611.5.1.el9_7, kernel-debuginfo-common-ppc64le 5.14.0-611.5.1.el9_7 Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-611.5.1.el9_7, kernel-rt-64k 5.14.0-611.5.1.el9_7, kernel-rt-core 5.14.0-611.5.1.el9_7, kernel-rt-modules 5.14.0-611.5.1.el9_7, kernel-rt-64k-core 5.14.0-611.5.1.el9_7, kernel-rt-debug-core 5.14.0-611.5.1.el9_7, +14 more Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-611.5.1.el9_7, kernel-rt-core 5.14.0-611.5.1.el9_7, kernel-rt-modules 5.14.0-611.5.1.el9_7, kernel-rt-debug-core 5.14.0-611.5.1.el9_7, kernel-rt-modules-core 5.14.0-611.5.1.el9_7, kernel-rt-debug-modules 5.14.0-611.5.1.el9_7, +4 more
    fixed: vendor fix RHSA-2025:20518
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 10 kernel
    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
13 mo ago

Exploit prediction

0.14% chance of exploitation in the next 30 days, higher than 3% of all scored CVEs (FIRST EPSS, 2026-11-08).

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 Vulns 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.