CVE & CISA-KEV Catalog

CVE-2011-4317

MEDIUMEPSS 99th pctl
4.3
CVSS v2
NVD

Description

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.

CWE-20Improper Input Validation

CVSS v2 Vector

No CVSS vector data available.

Exploit Intelligence

60.78%probability of exploitation in 30 days
99thpercentile

Very high risk: more likely to be exploited than 99% of all known CVEs.

References

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-29.