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CVE-2011-3639

55
FAUCET Score

CVE-2011-3639 describes a security bypass vulnerability in the mod_proxy module of Apache HTTP Server versions 2.0.x through 2.0.64 and 2.2.x before 2.2.18, specifically when a certain patch (Revision 1179239) is applied. This flaw, an incomplete fix for CVE-2011-3368, allows remote attackers to bypass reverse proxy configurations (RewriteRule and ProxyPassMatch) by sending malformed HTTP/0.9 requests with an initial '@' character in the URI, thereby accessing intranet servers. With a CVSS score of 4.3 (medium severity), this vulnerability has a network attack vector and medium attack complexity, potentially leading to information disclosure (partial impact) without requiring authentication. While there is no evidence of active exploitation or Metasploit/Nuclei modules, an exploit for Apache 2.2.15 mod_proxy exists on ExploitDB. The CVE has minimal community discussion and media coverage, indicating low public attention.

Impacted Technologies

VendorProductVersion(s)CPE
2.0.11CPE matchmatch criteria
cpe:2.3:a:apache:http_server:2.0.11:*:*:*:*:*:*:*
2.0.12CPE matchmatch criteria
cpe:2.3:a:apache:http_server:2.0.12:*:*:*:*:*:*:*
2.0.13CPE matchmatch criteria
cpe:2.3:a:apache:http_server:2.0.13:*:*:*:*:*:*:*
2.0.14CPE matchmatch criteria
cpe:2.3:a:apache:http_server:2.0.14:*:*:*:*:*:*:*
2.0.15CPE matchmatch criteria
cpe:2.3:a:apache:http_server:2.0.15:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 2.0

4.3MEDIUM

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

Confidentiality Impact
NONE
Integrity Impact
PARTIAL
Availability Impact
NONE
Access Vector
NETWORK
Access Complexity
MEDIUM
Authentication
NONE
Exploitability Score
8.6
Impact Score
2.9
CvssVersion
2.0

Exploit Intelligence

EPSS Score
50.60%
Probability of exploitation in next 30 days
EPSS Percentile
98.8%
Percentile rank of EPSS score among Peer Group
As of 2026-07-24
Model: v2026.06.15
ExploitDB: EDB-36663 · Feb 6, 2012
This CVE's current EPSS score of 0.5060 is in the 99th percentile among its peer group of 19,953 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.0 Bluesky, 0.0 Mastodon, and 0.2 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (3)

redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 5Fixed in: httpd-0:2.2.3-63.el5_8.1
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 6Fixed in: httpd-0:2.2.15-15.el6_2.1
View patch
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 4Fixed in: httpd

Vendor Advisories (1)

redhatCVE-2011-3639Moderate

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

Oct 26, 2011

References

rhn.redhat.com / errata/RHSA-2012-0128.html
bugzilla.redhat.com / show_bug.cgi
svn.apache.org / viewvc
debian.org / security/2012/dsa-2405