CVE-2025-21874: dm-integrity: Avoid divide by zero in table status in Inline mode

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-03-27 · updated 2026-06-17
Weakness: CWE-369

Description

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] ...

Affected products

Linux kernel: from 6.11 before 6.12.18; from 6.13 before 6.13.6; 6.14-rc1, 6.14-rc2, 6.14-rc3, 6.14-rc4 — fixed in 6.12.18, 6.13.6

How to fix

Upgrade to a fixed version: Linux kernel 6.12.18, 6.13.6. Check the vendor advisory for mitigations.

References

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