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Fencer Vulns
medium 5.5

CVE-2025-21963 json

cifs: Fix integer overflow while processing acdirmax mount option

published 2025-04-01 19 mo ago modified 2026-06-17 4 mo ago also EUVD-2025-9357

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 10%
public exploits
0
none known

Summary

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

cifs: Fix integer overflow while processing acdirmax mount option

User-provided mount parameter acdirmax of type u32 is intended to have an upper limit, but before it is validated, the value is converted from seconds to jiffies which can lead to an integer overflow.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Patch / fix

  • Linux Linux 5.15.180, 6.1.132, 6.6.84, 6.12.20, 6.13.8, 6.14
  • linux Debian 12 6.1.133-1
  • linux Debian 14, Debian 13 6.12.20-1

debian advisories DEBIAN-CVE-2025-21963

  • linux Ubuntu 22.04 LTS 5.15.0-142.152
  • linux Ubuntu 24.04 LTS 6.8.0-84.84
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1086.93
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1039.41
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1085.94
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1040.42
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1083.89
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1036.40

ubuntu advisories UBUNTU-CVE-2025-21963

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 5.14.0-570.22.1.el9_6
  • rv RHEL 9 5.14.0-570.22.1.el9_6
  • perf RHEL 9 5.14.0-570.22.1.el9_6
  • rtla RHEL 9 5.14.0-570.22.1.el9_6
  • libperf RHEL 9 5.14.0-570.22.1.el9_6
  • kernel-rt RHEL 9 5.14.0-570.22.1.el9_6
  • kernel-64k RHEL 9 5.14.0-570.22.1.el9_6
  • kernel-core RHEL 9 5.14.0-570.22.1.el9_6

red hat advisories RHSA-2025:9080RHSA-2025:9079

  • 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-rt Real Time Module 15 SP6, openSUSE Leap 15.6 6.4.0-150600.10.39.1

suse advisories SUSE-SU-2025:01972-1SUSE-SU-2025:01967-1SUSE-SU-2025:01964-1SUSE-SU-2025:01951-1SUSE-SU-2025:01919-1SUSE-SU-2025:01707-1

  • kernel AlmaLinux 9 5.14.0-570.22.1.el9_6
  • rv AlmaLinux 9 5.14.0-570.22.1.el9_6
  • perf AlmaLinux 9 5.14.0-570.22.1.el9_6
  • rtla AlmaLinux 9 5.14.0-570.22.1.el9_6
  • libperf AlmaLinux 9 5.14.0-570.22.1.el9_6
  • kernel-rt AlmaLinux 9 5.14.0-570.22.1.el9_6
  • kernel-64k AlmaLinux 9 5.14.0-570.22.1.el9_6
  • kernel-core AlmaLinux 9 5.14.0-570.22.1.el9_6

almalinux advisories ALSA-2025:9080

  • kernel Rocky Linux 10 6.12.0-55.17.1.el10_0

rocky linux advisories RLSA-2025:9079

  • kernel Azure Linux 3.0 6.6.85.1-2
  • kernel CBL-Mariner 2.0 5.15.180.1-1

azure linux advisories AZL-60282AZL-60316

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

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-2025-21963 updated cvss 5.5

kernel: cifs: Fix integer overflow while processing acdirmax mount option

  • Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-570.22.1.el9_6, perf 5.14.0-570.22.1.el9_6, rtla 5.14.0-570.22.1.el9_6, python3-perf 5.14.0-570.22.1.el9_6, kernel-devel-matched 5.14.0-570.22.1.el9_6, kernel-64k-devel-matched 5.14.0-570.22.1.el9_6, +7 more
    fixed: vendor fix RHSA-2025:9080
  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-55.17.1.el10_0, perf 6.12.0-55.17.1.el10_0, rtla 6.12.0-55.17.1.el10_0, python3-perf 6.12.0-55.17.1.el10_0, kernel-devel-matched 6.12.0-55.17.1.el10_0, kernel-64k-devel-matched 6.12.0-55.17.1.el10_0, +7 more
    fixed: vendor fix RHSA-2025:9079
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-570.22.1.el9_6, kernel-64k 5.14.0-570.22.1.el9_6, kernel-core 5.14.0-570.22.1.el9_6, kernel-tools 5.14.0-570.22.1.el9_6, kernel-modules 5.14.0-570.22.1.el9_6, kernel-64k-core 5.14.0-570.22.1.el9_6, +27 more
    fixed: vendor fix RHSA-2025:9080
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-55.17.1.el10_0, kernel-64k 6.12.0-55.17.1.el10_0, kernel-core 6.12.0-55.17.1.el10_0, kernel-tools 6.12.0-55.17.1.el10_0, kernel-modules 6.12.0-55.17.1.el10_0, kernel-64k-core 6.12.0-55.17.1.el10_0, +27 more
    fixed: vendor fix RHSA-2025:9079
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-570.22.1.el9_6, kernel-debuginfo-common-s390x 5.14.0-570.22.1.el9_6, kernel-debuginfo-common-x86_64 5.14.0-570.22.1.el9_6, kernel-debuginfo-common-aarch64 5.14.0-570.22.1.el9_6, kernel-debuginfo-common-ppc64le 5.14.0-570.22.1.el9_6
    fixed: vendor fix RHSA-2025:9080
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-55.17.1.el10_0, kernel-debuginfo-common-s390x 6.12.0-55.17.1.el10_0, kernel-debuginfo-common-x86_64 6.12.0-55.17.1.el10_0, kernel-debuginfo-common-aarch64 6.12.0-55.17.1.el10_0, kernel-debuginfo-common-ppc64le 6.12.0-55.17.1.el10_0
    fixed: vendor fix RHSA-2025:9079
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-570.22.1.el9_6, kernel-rt-64k 5.14.0-570.22.1.el9_6, kernel-rt-core 5.14.0-570.22.1.el9_6, kernel-rt-modules 5.14.0-570.22.1.el9_6, kernel-rt-64k-core 5.14.0-570.22.1.el9_6, kernel-rt-debug-core 5.14.0-570.22.1.el9_6, +14 more
    fixed: vendor fix RHSA-2025:9080
show 4 more
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-55.17.1.el10_0, kernel-rt-64k 6.12.0-55.17.1.el10_0, kernel-rt-core 6.12.0-55.17.1.el10_0, kernel-rt-modules 6.12.0-55.17.1.el10_0, kernel-rt-64k-core 6.12.0-55.17.1.el10_0, kernel-rt-debug-core 6.12.0-55.17.1.el10_0, +14 more
    fixed: vendor fix RHSA-2025:9079
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-570.22.1.el9_6, kernel-rt-kvm 5.14.0-570.22.1.el9_6, kernel-rt-core 5.14.0-570.22.1.el9_6, kernel-rt-modules 5.14.0-570.22.1.el9_6, kernel-rt-debug-kvm 5.14.0-570.22.1.el9_6, kernel-rt-debug-core 5.14.0-570.22.1.el9_6, +6 more
    fixed: vendor fix RHSA-2025:9080
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-55.17.1.el10_0, kernel-rt-kvm 6.12.0-55.17.1.el10_0, kernel-rt-core 6.12.0-55.17.1.el10_0, kernel-rt-modules 6.12.0-55.17.1.el10_0, kernel-rt-debug-kvm 6.12.0-55.17.1.el10_0, kernel-rt-debug-core 6.12.0-55.17.1.el10_0, +6 more
    fixed: vendor fix RHSA-2025:9079
  • 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
    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

0.21% chance of exploitation in the next 30 days, higher than 10% 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
  • CWE-190 Integer Overflow or Wraparound
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.