Public Date:
756483: CVE-2011-4317 httpd: uri scheme bypass of the reverse proxy vulnerability CVE-2011-3368 fix

The MITRE CVE dictionary describes this issue as:

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.

Find out more about CVE-2011-4317 from the MITRE CVE dictionary dictionary and NIST NVD.


This issue did not affect the versions of httpd as shipped with Red Hat Enterprise Linux 4 and 5 due to differences in apr-util's apr_uri_parse() implementation.

CVSS v2 metrics

NOTE: The following CVSS v2 metrics and score provided are preliminary and subject to review.

Base Score 2.6
Base Metrics AV:N/AC:H/Au:N/C:N/I:P/A:N
Access Vector Network
Access Complexity High
Authentication None
Confidentiality Impact None
Integrity Impact Partial
Availability Impact None

Find out more about Red Hat support for the Common Vulnerability Scoring System (CVSS).

Red Hat Security Errata

Platform Errata Release Date
Red Hat Enterprise Linux version 6 (httpd) RHSA-2012:0128 2012-02-13

Affected Packages State

Platform Package State
Red Hat Enterprise Linux 5 httpd Not affected
Red Hat Enterprise Linux 4 httpd Not affected

External References