CVE-2011-4885
MediumPublic exploitphp: hash table collisions CPU usage DoS (oCERT-2011-003)
Published Dec 28, 2011 · Updated Mar 9, 2026
Key Facts
Patch immediately- CVE-2011-4885 is a medium-severity vulnerability (CVSS 5.0 v2) affecting PHP, php5 (debian), php-bcmath (amazon) and 22 more products.
- It is not listed in any known-exploited vulnerabilities catalog. Public exploit code is available.
- EPSS estimates a 83% probability of exploitation in the next 30 days.
- Fixed versions are available, including apache2-mod_php5 5.6.28-1.1, apache2-mod_php7 7.0.14-1.4, PHP 0:4.3.9-3.35.
- Brandefense priority: patch immediately, because it is very likely to be exploited soon.
CVSS v2
5.0
AV:N/AC:L/Au:N/C:N/I:N/A:P
EPSS (30-day exploit likelihood)
83%
Higher than 99.6% of all scored CVEs
Exploited in the wild
No known
Not in a known-exploited catalog
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2011-4885 brief as a PDF
Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.
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.
Affected Products
327 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| PHPPHP | 5.0.0, 5.0.0-beta1, 5.0.0-beta2, 5.0.0-beta3, 5.0.0-beta4, 5.0.0-rc1, 5.0.0-rc2, 5.0.0-rc3 | 5.3.8 |
| php5debian | See advisory | 5.3.3-7+squeeze5 |
| php-bcmathamazon | See advisory | 5.3.9-1.9.amzn1 |
| php-cliamazon | See advisory | 5.3.9-1.9.amzn1 |
| php-commonamazon | See advisory | 5.3.9-1.9.amzn1 |
Patched Releases
apache2-mod_php5
5.6.28-1.1
apache2-mod_php7
7.0.14-1.4
PHP
0:4.3.9-3.35, 0:5.1.6-27.el5_7.4, 0:5.3.3-3.el6_2.5, 5.1.6-27.el5_7.4, 5.3.3-3.el6_2.5, 5.3.9-1.9.amzn1, 5.3.8
php-bcmath
5.1.6-27.el5_7.4, 5.3.3-3.el6_2.5, 5.3.9-1.9.amzn1
php-cli
5.1.6-27.el5_7.4, 5.3.3-3.el6_2.5, 5.3.9-1.9.amzn1
php-common
5.1.6-27.el5_7.4, 5.3.3-3.el6_2.5, 5.3.9-1.9.amzn1
php-dba
5.1.6-27.el5_7.4, 5.3.3-3.el6_2.5, 5.3.9-1.9.amzn1
php-devel
5.1.6-27.el5_7.4, 5.3.3-3.el6_2.5, 5.3.9-1.9.amzn1
php-embedded
5.3.3-3.el6_2.5, 5.3.9-1.9.amzn1
php-enchant
5.3.3-3.el6_2.5
php-fpm
5.3.9-1.9.amzn1
php-gd
5.1.6-27.el5_7.4, 5.3.3-3.el6_2.5, 5.3.9-1.9.amzn1
php-imap
5.1.6-27.el5_7.4, 5.3.3-3.el6_2.5, 5.3.9-1.9.amzn1
php-intl
5.3.3-3.el6_2.5, 5.3.9-1.9.amzn1
php-ldap
5.1.6-27.el5_7.4, 5.3.3-3.el6_2.5, 5.3.9-1.9.amzn1
php-mbstring
5.1.6-27.el5_7.4, 5.3.3-3.el6_2.5, 5.3.9-1.9.amzn1
php-mcrypt
5.3.9-1.9.amzn1
php-mssql
5.3.9-1.9.amzn1
php-mysql
5.1.6-27.el5_7.4, 5.3.3-3.el6_2.5, 5.3.9-1.9.amzn1
php-mysqlnd
5.3.9-1.9.amzn1
php-ncurses
5.1.6-27.el5_7.4
php-odbc
5.1.6-27.el5_7.4, 5.3.3-3.el6_2.5, 5.3.9-1.9.amzn1
php-pdo
5.1.6-27.el5_7.4, 5.3.3-3.el6_2.5, 5.3.9-1.9.amzn1
php-pgsql
5.1.6-27.el5_7.4, 5.3.3-3.el6_2.5, 5.3.9-1.9.amzn1
php-process
5.3.3-3.el6_2.5, 5.3.9-1.9.amzn1
Timeline
Publicly disclosed
Dec 28, 2011
Last updated
Mar 9, 2026
Weakness Type
- CWE-20 Improper Input Validation
References
- advisoryRHSA-2012:0019
- advisoryRHSA-2012:0033
- advisoryRHSA-2012:0071
- exploitExploitDB-18296
- exploitExploitDB-18305
FAQ
Common Questions.
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.
Affected: PHP versions 5.0.0, 5.0.0-beta1, 5.0.0-beta2, 5.0.0-beta3, 5.0.0-beta4, 5.0.0-rc1, 5.0.0-rc2, 5.0.0-rc3; php5 (debian); php-bcmath (amazon), among others. The full list is in the CVE brief.
It is not listed in any known-exploited vulnerabilities catalog.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
Public exploit code is available.
Fixed versions are available, including apache2-mod_php5 5.6.28-1.1, apache2-mod_php7 7.0.14-1.4, PHP 0:4.3.9-3.35.
Brandefense priority: patch immediately, because it is very likely to be exploited soon.
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