CVE-2026-99086

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.