CVE-2026-89574: Linux kernel · dm array: validate array block headers on read
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 7.8 High · fixed in b33f76d33aaeacf3baf3370d8d64985169b36600 : patch Linux kernel soon.
Data as of 26 Oct 2026, 12:55 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Total control over the software or total information disclosure
CISA SSVC assessment, 2026-10-16.
- Patch
- Available – fixed in b33f76d33aaeacf3baf3370d8d64985169b36600, 2965787723084835b18dfe993cd450ebf5bd4540, 9808ddffb4bc659352df3020cd84d9d864820ee5 +2
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 11 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in– |
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.
References
- git.kernel.org/stable/c/0e3b8f371c385c212b6e6f76c66f5b3f5bcfea62 (opens in a new tab)
- git.kernel.org/stable/c/67adda7ed5da3e3b64f5b9021a02c21fb374fd9c (opens in a new tab)
- git.kernel.org/stable/c/b33f76d33aaeacf3baf3370d8d64985169b36600 (opens in a new tab)
- git.kernel.org/stable/c/9808ddffb4bc659352df3020cd84d9d864820ee5 (opens in a new tab)
- git.kernel.org/stable/c/2965787723084835b18dfe993cd450ebf5bd4540 (opens in a new tab)