Description
Integer signedness error in zip_stream.c in the Zip extension in PHP before 5.3.6 allows context-dependent attackers to cause a denial of service (CPU consumption) via a malformed archive file that triggers errors in zip_fread function calls.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 6.0 | php5 | 5.3.3-7+squeeze3 | DSA-2266-1 |
| Debian 5.0 | php5 | 5.2.6.dfsg.1-1+lenny12 | DSA-2266-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 6 | php +25 | 5.3.3-3.el6_1.3 | RHSA-2011:1423 |
| RHEL 5 | php53 +20 | 5.3.3-1.el5_7.3 | RHSA-2011:1423 |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
Exploit-DB 1
- PHP < 5.3.6 'Zip' Extension - 'zip_fread()' Denial of Service EDB-35485 · dos · Mar 10, 2011 · verified
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 2
- RHSA-2011:1423 Red Hat Security Advisory: php53 and php security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- DSA-2266-1 php5 - several Debian Security (DSA / DLA) · Mar 9, 2026
References
- 46975 vdb-entry
- MDVSA-2011:053 vendor-advisory
- DSA-2266 vendor-advisory
- http://www.php.net/ChangeLog-5.php
- APPLE-SA-2011-10-12-3 vendor-advisory
- RHSA-2011:1423 vendor-advisory
- MDVSA-2011:052 vendor-advisory
- ADV-2011-0744 vdb-entry
- http://support.apple.com/kb/HT5002
- http://bugs.php.net/bug.php?id=49072