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Fencer Intel
medium 4.3

CVE-2011-4317 json

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 1179…

published 2011-11-30 14 y ago modified 2026-06-16 4 mo ago also EUVD-2011-4251

cvss
4.3
version 2.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
59.6%
EPSS 59.6% chance of exploitation in 30 days, percentile 99.1%
public exploits
1
Exploit-DB

Summary

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.

Patch / fix

  • apache2 Debian 14, Debian 13, Debian 12 2.2.21-3

debian advisories DEBIAN-CVE-2011-4317

  • httpd RHEL 6 2.2.15-15.el6_2.1
  • mod_ssl RHEL 6 1:2.2.15-15.el6_2.1
  • httpd-tools RHEL 6 2.2.15-15.el6_2.1
  • httpd-manual RHEL 6 2.2.15-15.el6_2.1

red hat advisories RHSA-2012:0128

  • apache2 openSUSE Tumbleweed 2.4.23-4.1

opensuse advisories openSUSE-SU-2024:10268-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2011-4317 updated cvss 2.6

httpd: uri scheme bypass of the reverse proxy vulnerability CVE-2011-3368 fix

  • Red Hat Enterprise Linux Desktop (v. 6) httpd 2.2.15-15.el6_2.1, httpd-tools 2.2.15-15.el6_2.1 Red Hat Enterprise Linux Desktop Optional (v. 6) httpd 2.2.15-15.el6_2.1, mod_ssl 2.2.15-15.el6_2.1, httpd-manual 2.2.15-15.el6_2.1 Red Hat Enterprise Linux HPC Node (v. 6) httpd 2.2.15-15.el6_2.1, httpd-tools 2.2.15-15.el6_2.1 Red Hat Enterprise Linux HPC Node Optional (v. 6) httpd 2.2.15-15.el6_2.1, mod_ssl 2.2.15-15.el6_2.1, httpd-manual 2.2.15-15.el6_2.1 Red Hat Enterprise Linux Server (v. 6) httpd 2.2.15-15.el6_2.1, mod_ssl 2.2.15-15.el6_2.1, httpd-tools 2.2.15-15.el6_2.1, httpd-manual 2.2.15-15.el6_2.1 Red Hat Enterprise Linux Workstation (v. 6) httpd 2.2.15-15.el6_2.1, mod_ssl 2.2.15-15.el6_2.1, httpd-tools 2.2.15-15.el6_2.1, httpd-manual 2.2.15-15.el6_2.1
    fixed: vendor fix RHSA-2012:0128
  • Red Hat Directory Server 8 httpd Red Hat Enterprise Linux 4 httpd Red Hat Enterprise Linux 5 httpd Red Hat JBoss Enterprise Web Server 1 httpd
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Timeline

  1. First public exploit (EDB-36352)
  2. Published

Exploit prediction

59.63% chance of exploitation in the next 30 days, higher than 99.1% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • EDB-36352 Apache 7.0.x mod_proxy - Reverse Proxy Security Bypass remote, 2011-11-24
  • community.qualys.com https://community.qualys.com/blogs/securitylabs/2011/11/23/apache-reverse-proxy-bypass-issue referenced PoC, tagged "exploit" by a source, unverified
  • thread.gmane.org http://thread.gmane.org/gmane.comp.apache.devel/46440 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:P/A:N

Classification

Weakness
  • CWE-20 Improper Input Validation
Technology feeds

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.