# CVE-2026-23269: apparmor: validate DFA start states are in bounds in unpack_pdb

> An out-of-bounds read in the Linux kernel AppArmor module allows attackers to cause a denial of service or disclose sensitive memory information.

- **Severity:** High 7.1 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 18 Mar 2026
- **Updated:** 5 Aug 2026
- **Also known as:** AZL-80082, BELL-CVE-2026-23269, DEBIAN-CVE-2026-23269, GHSA-cq3w-r62m-5jvq, UBUNTU-CVE-2026-23269

## What is CVE-2026-23269?

CVE-2026-23269 is a high-severity memory corruption vulnerability in Linux kernel, published on 18 Mar 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official 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.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-23269?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-23269?

Apply the vendor's patch.

## Is CVE-2026-23269 being exploited?

There is no known exploitation of CVE-2026-23269 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-23269 and fix it if it is affected.

What it is: CVE-2026-23269 is a high-severity memory corruption vulnerability in Linux kernel, published on 18 Mar 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-23269 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-23269/ (Markdown: https://insights.sbomify.com/CVE-2026-23269/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-23269
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-23269
- OSV: https://osv.dev/vulnerability/CVE-2026-23269

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-23269/
Summaries are generated and may contain mistakes; the official description above is the record.