CVE-2011-4885

PHP < 5.3.9 - Denial of Service via Hash Collision in Form Parameter Handling

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 4 public exploits for CVE-2011-4885. PoCs published by Christian Mehlmauer, infodox, Alexander Klink, Julian Waelde, Scott A. Crosby, Dan S. Wallach, Krzysztof Kotowicz, Christian Mehlmauer, including Metasploit module auxiliary/dos/http/hashcollision_dos.

AI-analyzed exploit summary This script exploits a hash collision vulnerability (CVE-2011-4885) in PHP by generating malicious POST data that causes excessive CPU usage due to hash table collisions. It supports multiple targets (PHP, Java, ASP) and can perform DoS attacks by sending multiple requests.

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.

Exploits (4)

exploitdb WORKING POC VERIFIED
by Christian Mehlmauer · pythondosphp
https://www.exploit-db.com/exploits/18305

This script exploits a hash collision vulnerability (CVE-2011-4885) in PHP by generating malicious POST data that causes excessive CPU usage due to hash table collisions. It supports multiple targets (PHP, Java, ASP) and can perform DoS attacks by sending multiple requests.

Classification
Working Poc 95%
Attack Type
Dos
Complexity
Moderate
Reliability
Reliable
Target: PHP (versions affected by CVE-2011-4885)
No auth needed
Prerequisites: Network access to the target server · PHP with vulnerable hash implementation
devstral-2 · analyzed Feb 16, 2026 Full analysis →
exploitdb WORKING POC
by infodox · textdosphp
https://www.exploit-db.com/exploits/18296

This exploit leverages a hash collision vulnerability in PHP 5.3.* to perform a Denial of Service (DoS) attack by sending specially crafted POST data to the target server. It repeatedly sends the payload to exhaust server resources.

Classification
Working Poc 90%
Attack Type
Dos
Complexity
Trivial
Reliability
Reliable
Target: PHP 5.3.*
No auth needed
Prerequisites: Target server running PHP 5.3.* · Network access to the target
devstral-2 · analyzed Feb 16, 2026 Full analysis →
exploitdb WORKING POC
phpwebappsphp
https://www.exploit-db.com/exploits/2012

This exploit demonstrates a SQL injection vulnerability in MyBulletinBoard (MyBB) <= 1.1.5 via the CLIENT-IP HTTP header, allowing an attacker to extract the admin login key and create a new admin user.

Classification
Working Poc 100%
Attack Type
Sqli
Complexity
Moderate
Reliability
Reliable
Target: MyBulletinBoard (MyBB) <= 1.1.5
No auth needed
Prerequisites: Network access to the target MyBB instance
devstral-2 · analyzed Feb 19, 2026 Full analysis →
metasploit WORKING POC
by Alexander Klink, Julian Waelde, Scott A. Crosby, Dan S. Wallach, Krzysztof Kotowicz, Christian Mehlmauer · rubypoc
https://github.com/rapid7/metasploit-framework/blob/master/modules/auxiliary/dos/http/hashcollision_dos.rb

This Metasploit module exploits a denial-of-service (DoS) vulnerability in PHP and Java web servers by generating hash collisions in POST parameters, causing excessive CPU consumption. It supports both PHP and Java hash functions and includes configurable payload generation.

Classification
Working Poc 100%
Attack Type
Dos
Complexity
Moderate
Reliability
Reliable
Target: PHP (with httpd), Java (Tomcat, Glassfish, Geronimo)
No auth needed
Prerequisites: Network access to the target web server
devstral-2 · analyzed Feb 16, 2026 Full analysis →

References (27)

Core 27
Core References
Various Sources x_refsource_misc
http://www.nruns.com/_downloads/advisory28122011.pdf
Various Sources x_refsource_confirm
http://svn.php.net/viewvc?view=revision&revision=321003
Various Sources x_refsource_confirm
http://svn.php.net/viewvc?view=revision&revision=321040
Various Sources x_refsource_misc
http://www.ocert.org/advisories/ocert-2011-003.html
Third Party Advisory, VDB Entry vdb-entry x_refsource_sectrack
http://www.securitytracker.com/id?1026473
Third Party Advisory third-party-advisory x_refsource_secunia
http://secunia.com/advisories/47404
Mailing List vendor-advisory x_refsource_hp
http://marc.info/?l=bugtraq&m=133469208622507&w=2
Third Party Advisory, VDB Entry vdb-entry x_refsource_xf
https://exchange.xforce.ibmcloud.com/vulnerabilities/72021
Exploit, Third Party Advisory exploit x_refsource_exploit-db
http://www.exploit-db.com/exploits/18296
Third Party Advisory vendor-advisory x_refsource_debian
http://www.debian.org/security/2012/dsa-2399
Vendor Advisory vendor-advisory x_refsource_mandriva
http://www.mandriva.com/security/advisories?name=MDVSA-2011:197
Exploit, Third Party Advisory exploit x_refsource_exploit-db
http://www.exploit-db.com/exploits/18305
Third Party Advisory third-party-advisory x_refsource_secunia
http://secunia.com/advisories/48668
Vendor Advisory vendor-advisory x_refsource_redhat
http://www.redhat.com/support/errata/RHSA-2012-0019.html
Third Party Advisory, VDB Entry vdb-entry x_refsource_bid
http://www.securityfocus.com/bid/51193
US Government Resource third-party-advisory x_refsource_cert-vn
http://www.kb.cert.org/vuls/id/903934
Vendor Advisory vendor-advisory x_refsource_redhat
http://rhn.redhat.com/errata/RHSA-2012-0071.html
Mailing List vendor-advisory x_refsource_hp
http://marc.info/?l=bugtraq&m=132871655717248&w=2
Third Party Advisory mailing-list x_refsource_bugtraq
http://archives.neohapsis.com/archives/bugtraq/2011-12/0181.html
Vendor Advisory x_refsource_confirm
http://support.apple.com/kb/HT5281
Vendor Advisory vendor-advisory x_refsource_mandriva
http://www.mandriva.com/security/advisories?name=MDVSA-2013:150
Mailing List vendor-advisory x_refsource_apple
http://lists.apple.com/archives/security-announce/2012/May/msg00001.html

Scores

EPSS 0.8657
EPSS Percentile 99.4%

Details

CWE
CWE-20
Status published
Products (38)
php/php 5.0.0 (8 CPE variants)
php/php 5.0.1
php/php 5.0.2
php/php 5.0.3
php/php 5.0.4
php/php 5.0.5
php/php 5.1.1
php/php 5.1.2
php/php 5.1.3
php/php 5.1.4
... and 28 more
Published Dec 30, 2011
Tracked Since Feb 18, 2026