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Fencer Intel
medium 4.3

CVE-2011-3639 json

The mod_proxy module in the Apache HTTP Server 2.0.x through 2.0.64 and 2.2.x before 2.2.18, when the Revision 1179239 patch is in place, d…

published 2011-11-30 14 y ago modified 2026-06-16 4 mo ago also EUVD-2011-3598

cvss
4.3
version 2.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
49.7%
EPSS 49.7% chance of exploitation in 30 days, percentile 98%
public exploits
1
Exploit-DB

Summary

The mod_proxy module in the Apache HTTP Server 2.0.x through 2.0.64 and 2.2.x before 2.2.18, 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 by using the HTTP/0.9 protocol with a malformed URI containing an initial @ (at sign) character. NOTE: this vulnerability exists because of an incomplete fix for CVE-2011-3368.

Patch / fix

  • apache2 Debian 14, Debian 13, Debian 12 2.2.18-1

debian advisories DEBIAN-CVE-2011-3639

  • httpd RHEL 5 2.2.3-63.el5_8.1
  • mod_ssl RHEL 5 1:2.2.3-63.el5_8.1
  • httpd-manual RHEL 5 2.2.3-63.el5_8.1
  • 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-2012:0323RHSA-2012:0128

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-2011-3639 updated cvss 2.6

httpd: http 0.9 request bypass of the reverse proxy vulnerability CVE-2011-3368 fix

  • Red Hat Enterprise Linux 4 httpd
    affected: no fix planned “Will not fix”
  • Red Hat Enterprise Linux (v. 5 server) httpd 2.2.3-63.el5_8.1, mod_ssl 2.2.3-63.el5_8.1, httpd-manual 2.2.3-63.el5_8.1 Red Hat Enterprise Linux Desktop (v. 5 client) httpd 2.2.3-63.el5_8.1, mod_ssl 2.2.3-63.el5_8.1
    fixed: vendor fix RHSA-2012:0323
  • 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 RHEL Desktop Workstation (v. 5 client) httpd 2.2.3-63.el5_8.1, httpd-manual 2.2.3-63.el5_8.1
    fixed: vendor fix RHSA-2012:0323
  • Red Hat Directory Server 8 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. Published
  2. First public exploit (EDB-36663)

Exploit prediction

49.70% chance of exploitation in the next 30 days, higher than 98% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • EDB-36663 Apache 2.2.15 mod_proxy - Reverse Proxy Security Bypass remote, 2012-02-06

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.