Which products and versions are affected by CVE-2011-3639?

Affected: HTTP Server (Apache) versions 2.0.11, 2.0.12, 2.0.13, 2.0.14, 2.0.15, 2.0.16, 2.0.17, 2.0.18; HTTP Server2.0a1 (Apache); HTTP Server2.0a2 (Apache), among others. The full list is in the CVE brief.

Is CVE-2011-3639 being exploited in the wild?

It is not listed in any known-exploited vulnerabilities catalog.

Is CVE-2011-3639 in the CISA KEV catalog?

No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.

Is there a public exploit for CVE-2011-3639?

Public exploit code is available.

Is there a fix for CVE-2011-3639?

Fixed versions are available, including apache2 2.2.16-6+squeeze6, apache2 2.2.18-1, apache2 2.2.9-10+lenny12.

How urgently should CVE-2011-3639 be patched?

Brandefense priority: patch immediately, because it is very likely to be exploited soon.

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Vulnerability Intelligence

CVE-2011-3639

MediumPublic exploit

Published Nov 30, 2011 · Updated Aug 4, 2026 · Also known as DEBIAN-CVE-2011-3639

Key Facts

Patch immediately

CVE-2011-3639 is a medium-severity vulnerability (CVSS 4.3 v2) affecting HTTP Server (Apache), HTTP Server2.0a1 (Apache), HTTP Server2.0a2 (Apache) and 14 more products.
It is not listed in any known-exploited vulnerabilities catalog. Public exploit code is available.
EPSS estimates a 51% probability of exploitation in the next 30 days.
Fixed versions are available, including apache2 2.2.16-6+squeeze6, apache2 2.2.18-1, apache2 2.2.9-10+lenny12.
Brandefense priority: patch immediately, because it is very likely to be exploited soon.

CVSS v2

4.3

AV:N/AC:M/Au:N/C:N/I:P/A:N

EPSS (30-day exploit likelihood)

51%

Higher than 98.9% of all scored CVEs

Exploited in the wild

No known

Not in a known-exploited catalog

Public exploit code

Available

Proof-of-concept or weaponized module

Get the full CVE-2011-3639 brief as a PDF

Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.

Description

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.

Affected Products

105 affected entries in total

Product	Affected versions	Fixed in
HTTP ServerApache	2.0.11, 2.0.12, 2.0.13, 2.0.14, 2.0.15, 2.0.16, 2.0.17, 2.0.18	n/a
HTTP Server2.0a1Apache	See advisory	n/a
HTTP Server2.0a2Apache	See advisory	n/a
HTTP Server2.0a3Apache	See advisory	n/a
HTTP Server2.0a4Apache	See advisory	n/a

12 more affected products in the full CVE brief

Patched Releases

apache2

2.2.16-6+squeeze6, 2.2.18-1, 2.2.9-10+lenny12

httpd

0:2.2.15-15.el6_2.1, 0:2.2.3-63.el5_8.1, 2.2.15-15.0.1.el6_2.1, 2.2.22-1.23.amzn1, 2.2.3-63.0.1.el5_8.1

httpd-devel

2.2.15-15.0.1.el6_2.1, 2.2.22-1.23.amzn1, 2.2.3-63.0.1.el5_8.1

httpd-manual

2.2.15-15.0.1.el6_2.1, 2.2.22-1.23.amzn1, 2.2.3-63.0.1.el5_8.1

httpd-tools

2.2.15-15.0.1.el6_2.1, 2.2.22-1.23.amzn1

mod_ssl

1:2.2.15-15.0.1.el6_2.1, 1:2.2.22-1.23.amzn1, 1:2.2.3-63.0.1.el5_8.1

rootio-apache2

2.2.18-1

Timeline

Publicly disclosed
Nov 30, 2011
Last updated
Aug 4, 2026

Weakness Type

CWE-20 Improper Input Validation

References

advisoryRHSA-2012:0128
advisoryRHSA-2012:0323
advisoryhttps://security-tracker.debian.org/tracker/CVE-2011-3639
exploitExploitDB-36663
otherRHSA-2012:0128

3 more references in the full CVE brief

FAQ

Common Questions.

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…
Affected: HTTP Server (Apache) versions 2.0.11, 2.0.12, 2.0.13, 2.0.14, 2.0.15, 2.0.16, 2.0.17, 2.0.18; HTTP Server2.0a1 (Apache); HTTP Server2.0a2 (Apache), among others. The full list is in the CVE brief.
It is not listed in any known-exploited vulnerabilities catalog.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
Public exploit code is available.
Fixed versions are available, including apache2 2.2.16-6+squeeze6, apache2 2.2.18-1, apache2 2.2.9-10+lenny12.
Brandefense priority: patch immediately, because it is very likely to be exploited soon.

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