Description
ModSecurity before 2.6.6, when used with PHP, does not properly handle single quotes not at the beginning of a request parameter value in the Content-Disposition field of a request with a multipart/form-data Content-Type header, which allows remote attackers to bypass filtering rules and perform other attacks such as cross-site scripting (XSS) attacks. NOTE: this vulnerability exists because of an incomplete fix for CVE-2009-5031.
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 14 | modsecurity-apache | 2.6.6-1 | — |
| Debian 13 | modsecurity-apache | 2.6.6-1 | — |
| Debian 12 | modsecurity-apache | 2.6.6-1 | — |
| Debian 6.0 | libapache-mod-security | 2.5.12-1+squeeze1 | DSA-2506-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | apache2-mod_security2 | 2.9.0-5.6 | openSUSE-SU-2024:10034-1 |
Advisories 2
- DSA-2506-1 libapache-mod-security - modsecurity bypass Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2024:10034-1 apache2-mod_security2-2.9.0-5.6 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
References
- openSUSE-SU-2013:1342 vendor-advisory
- 54156 vdb-entry
- DSA-2506 vendor-advisory
- openSUSE-SU-2013:1331 vendor-advisory
- http://mod-security.svn.sourceforge.net/viewvc/mod-security/m2/branches/2.6.x/CHANGES
- 49782 third-party-advisory
- http://mod-security.svn.sourceforge.net/viewvc/mod-security/m2/trunk/apache2/msc_multipart.c?r1=1918&r2=1917&pathrev=1918
- http://blog.ivanristic.com/2012/06/modsecurity-and-modsecurity-core-rule-set-multipart-bypasses.html
- [oss-security] 20120621 Re: mod_security CVE request mailing-list
- http://www.oracle.com/technetwork/topics/security/cpuapr2013-1899555.html
- http://mod-security.svn.sourceforge.net/viewvc/mod-security/m2/trunk/CHANGES?r1=1920&r2=1919&pathrev=1920
- [oss-security] 20120621 mod_security CVE request mailing-list
- MDVSA-2012:118 vendor-advisory
- 49576 third-party-advisory
- MDVSA-2013:150 vendor-advisory
- openSUSE-SU-2013:1336 vendor-advisory