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Fencer Vulns
medium 5.5

CVE-2025-21874 json

dm-integrity: Avoid divide by zero in table status in Inline mode

published 2025-03-27 19 mo ago modified 2026-11-05 3 d ago also EUVD-2025-8485

cvss
5.5
version 3.1, NVD
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:

dm-integrity: Avoid divide by zero in table status in Inline mode

In Inline mode, the journal is unused, and journal_sectors is zero.

Calculating the journal watermark requires dividing by journal_sectors, which should be done only if the journal is configured.

Otherwise, a simple table query (dmsetup table) can cause OOPS.

This bug did not show on some systems, perhaps only due to compiler optimization.

On my 32-bit testing machine, this reliably crashes with the following:

: Oops: divide error: 0000 [#1] PREEMPT SMP : CPU: 0 UID: 0 PID: 2450 Comm: dmsetup Not tainted 6.14.0-rc2+ #959 : EIP: dm_integrity_status+0x2f8/0xab0 [dm_integrity] ...

Patch / fix

  • Linux Linux 6.12.18, 6.13.6, 6.14
  • linux Debian 14, Debian 13 6.12.19-1

debian advisories DEBIAN-CVE-2025-21874

  • linux-gcp-6.11 Ubuntu 24.04 LTS 6.11.0-1015.15~24.04.1
  • linux-hwe-6.11 Ubuntu 24.04 LTS 6.11.0-26.26~24.04.1
  • linux-oem-6.11 Ubuntu 24.04 LTS 6.11.0-1022.22
  • linux-azure-6.11 Ubuntu 24.04 LTS 6.11.0-1015.15~24.04.1
  • linux-nvidia-6.11 Ubuntu 24.04 LTS 6.11.0-1010.10
  • linux-lowlatency-hwe-6.11 Ubuntu 24.04 LTS 6.11.0-1014.15~24.04.1

ubuntu advisories UBUNTU-CVE-2025-21874

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

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-2025-21874 updated cvss 5.5

kernel: dm-integrity: Avoid divide by zero in table status in Inline mode

  • 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 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
    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
3 d ago

Exploit prediction

0.20% 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
NVD 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.