Description
The mod_proxy module in the Apache HTTP Server 1.3.x through 1.3.42, 2.0.x through 2.0.64, and 2.2.x through 2.2.21, when the Revision 1179239 patch is in place, does not properly interact with use of (1) RewriteRule and (2) ProxyPassMatch pattern matches for configuration of a reverse proxy, which allows remote attackers to send requests to intranet servers via a malformed URI containing an @ (at sign) character and a : (colon) character in invalid positions. NOTE: this vulnerability exists because of an incomplete fix for CVE-2011-3368.
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 | apache2 | 2.2.21-3 | — |
| Debian 13 | apache2 | 2.2.21-3 | — |
| Debian 12 | apache2 | 2.2.21-3 | — |
| Debian 6.0 | apache2 | 2.2.16-6+squeeze6 | DSA-2405-1 |
| Debian 5.0 | apache2 | 2.2.9-10+lenny12 | DSA-2405-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 6 | httpd +3 | 2.2.15-15.el6_2.1 | RHSA-2012:0128 |
| RHEL 6 | mod_ssl | 1:2.2.15-15.el6_2.1 | RHSA-2012:0128 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | apache2 | 2.4.23-4.1 | openSUSE-SU-2024:10268-1 |
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
- Apache 7.0.x mod_proxy - Reverse Proxy Security Bypass EDB-36352 · remote · Nov 24, 2011 · verified
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 3
- RHSA-2012:0128 Red Hat Security Advisory: httpd security update Red Hat Security Advisories (RHSA) · Aug 5, 2026
- DSA-2405-1 apache2 - multiple issues Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2024:10268-1 apache2-2.4.23-4.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
References
- https://community.qualys.com/blogs/securitylabs/2011/11/23/apache-reverse-proxy-bypass-issue
- HPSBMU02786 vendor-advisory
- SSRT100966 vendor-advisory
- SSRT100772 vendor-advisory
- RHSA-2012:0128 vendor-advisory
- http://www.oracle.com/technetwork/topics/security/cpujan2015-1972971.html
- https://bugzilla.redhat.com/show_bug.cgi?id=756483
- http://thread.gmane.org/gmane.comp.apache.devel/46440
- APPLE-SA-2012-09-19-2 vendor-advisory
- http://support.apple.com/kb/HT5501
- http://www.oracle.com/technetwork/topics/security/cpujul2012-392727.html
- openSUSE-SU-2013:0248 vendor-advisory
- 1026353 vdb-entry
- openSUSE-SU-2013:0243 vendor-advisory
- MDVSA-2013:150 vendor-advisory
- 48551 third-party-advisory
- DSA-2405 vendor-advisory
- http://kb.juniper.net/JSA10585
- MDVSA-2012:003 vendor-advisory
- [httpd-cvs] 20190815 svn commit: r1048743 [3/4] - in /websites/staging/httpd/trunk/content: ./ security/vulnerabilities-httpd.xml security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilit mailing-list
- [httpd-cvs] 20190815 svn commit: r1048742 [3/4] - in /websites/staging/httpd/trunk/content: ./ security/vulnerabilities-httpd.xml security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilit mailing-list
- [httpd-cvs] 20200401 svn commit: r1058586 [3/4] - in /websites/staging/httpd/trunk/content: ./ security/vulnerabilities-httpd.xml security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilit mailing-list
- [httpd-cvs] 20200401 svn commit: r1058587 [3/4] - in /websites/staging/httpd/trunk/content: ./ security/vulnerabilities-httpd.xml security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilit mailing-list
- [httpd-cvs] 20210330 svn commit: r1073139 [1/13] - in /websites/staging/httpd/trunk/content: ./ security/json/ mailing-list
- [httpd-cvs] 20210330 svn commit: r1073140 [3/4] - in /websites/staging/httpd/trunk/content: ./ security/cvejsontohtml.py security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilities_24.ht mailing-list
- [httpd-cvs] 20210330 svn commit: r1073139 [8/13] - in /websites/staging/httpd/trunk/content: ./ security/json/ mailing-list
- [httpd-cvs] 20210330 svn commit: r1888194 [8/13] - /httpd/site/trunk/content/security/json/ mailing-list
- [httpd-cvs] 20210330 svn commit: r1073149 [8/13] - in /websites/staging/httpd/trunk/content: ./ security/ security/json/ mailing-list
- [httpd-cvs] 20210330 svn commit: r1073146 [2/3] - in /websites/staging/httpd/trunk/content: ./ security/cvejsontohtml.py security/vulnerabilities-httpd.xml security/vulnerabilities_22.html security/vulnerabilities_24.html mailing-list
- [httpd-cvs] 20210330 svn commit: r1073149 [1/13] - in /websites/staging/httpd/trunk/content: ./ security/ security/json/ mailing-list
- [httpd-cvs] 20210603 svn commit: r1075360 [2/3] - in /websites/staging/httpd/trunk/content: ./ security/json/CVE-2021-31618.json security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabiliti mailing-list
- [httpd-cvs] 20210606 svn commit: r1075467 [2/2] - in /websites/staging/httpd/trunk/content: ./ security/json/CVE-2021-31618.json security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabiliti mailing-list
- [httpd-cvs] 20210606 svn commit: r1075470 [3/4] - in /websites/staging/httpd/trunk/content: ./ security/json/CVE-2020-13938.json security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabiliti mailing-list