Bug 2559809 (CVE-2026-99086) - CVE-2026-99086 kernel: dm-integrity: validate the superblock on resume
Summary: CVE-2026-99086 kernel: dm-integrity: validate the superblock on resume
Keywords:
Status: NEW
Alias: CVE-2026-99086
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-10-23 13:44 UTC by OSIDB Bzimport
Modified: 2026-10-26 17:53 UTC (History)
17 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:


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Description OSIDB Bzimport 2026-10-23 13:44:13 UTC
In the Linux kernel, the following vulnerability has been resolved:

dm-integrity: validate the superblock on resume

dm_integrity_resume() re-reads the superblock from the device so that it
picks up the flags and the recalculate position. It performs no
validation on the result, while the constructor validates the superblock
it reads and sizes all the in-memory structures according to it. The user
may modify the superblock on the underlying device while the dm-integrity
device is suspended, so that the two no longer agree.

In particular, access_journal_data() shifts the journal entry index by
ic->sb->log2_sectors_per_block, while ic->journal_section_sectors and the
journal page list were computed with the value that was present at
constructor time. Increasing log2_sectors_per_block makes the index run
past the end of the journal, and dm-integrity then writes 512 bytes
through lowmem_page_address(NULL).

Snapshot the validated superblock in the constructor and refuse to resume
if any of the fields that describe the on-disk geometry changed.


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