# CVE-2026-89574

## Summary

- **CVE ID:** CVE-2026-89574
- **Severity:** HIGH
- **CVSS Score:** 7.8 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)
- **CWE:** N/A
- **Published:** Sep 11, 2026
- **Last Modified:** Sep 13, 2026

## Description

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

dm array: validate array block headers on read

array_block_check() validates blocknr and csum and nothing else, while
node_check(), next to it, has bounded the structural fields since both
were written. dm_array_cursor_next() takes its loop bound from the
on-disk nr_entries and element_at() is unguarded pointer arithmetic, so
a count larger than the block holds keeps the cursor in one block while
the index grows past it and the read walks off the dm-bufio buffer --
dm_cache_load_mappings() drives it once per cache block at activation.

Check the header against itself: reject a zero value_size, require
max_entries to equal calc_max_entries() for that value_size and block
size, and require nr_entries to fit. Equality rather than an upper bound,
since a count below the real capacity trips BUG_ON() in fill_ablock() and
trim_ablock(). Metadata dm-array writes satisfies all three.

## Affected Products

- Linux — Linux (6513c29f44f2cc970c0e9fecfe5a6526c3e73025)
- Linux — Linux (3.9)
- Linux — Linux (0)
- Linux — Linux (6.12.109)
- Linux — Linux (6.18.50)
- Linux — Linux (7.2.4)
- Linux — Linux (7.3-rc1)

## References

- [CNA](https://git.kernel.org/stable/c/67adda7ed5da3e3b64f5b9021a02c21fb374fd9c)
- [CNA](https://git.kernel.org/stable/c/b33f76d33aaeacf3baf3370d8d64985169b36600)
- [CNA](https://git.kernel.org/stable/c/9808ddffb4bc659352df3020cd84d9d864820ee5)
- [CNA](https://git.kernel.org/stable/c/2965787723084835b18dfe993cd450ebf5bd4540)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.16%
- **EPSS Percentile:** 5.9

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-17._