CVE-2016-4975

MEDIUM NUCLEI

Apache HTTP Server <2.4.24, <2.2.32 - CRLF Injection

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2016-4975. PoCs published by BlackFan. A Nuclei detection template is also available.

AI-analyzed exploit summary The repository provides a technical writeup detailing CRLF injection vulnerabilities in Apache httpd's mod_userdir module. It includes configuration snippets and HTTP request examples demonstrating how to exploit the vulnerability to inject arbitrary headers.

Description

Possible CRLF injection allowing HTTP response splitting attacks for sites which use mod_userdir. This issue was mitigated by changes made in 2.4.25 and 2.2.32 which prohibit CR or LF injection into the "Location" or other outbound header key or value. Fixed in Apache HTTP Server 2.4.25 (Affected 2.4.1-2.4.23). Fixed in Apache HTTP Server 2.2.32 (Affected 2.2.0-2.2.31).

Exploits (1)

github WRITEUP 21 stars
by BlackFan · poc
https://github.com/BlackFan/CVE_PoCs/tree/master/CVE-2016-4975 (Apache httpd)

The repository provides a technical writeup detailing CRLF injection vulnerabilities in Apache httpd's mod_userdir module. It includes configuration snippets and HTTP request examples demonstrating how to exploit the vulnerability to inject arbitrary headers.

Classification
Writeup 90%
Attack Type
Other
Complexity
Trivial
Reliability
Reliable
Target: Apache httpd 2.2.0-2.2.31, 2.4.1-2.4.23
No auth needed
Prerequisites: Apache httpd with mod_userdir enabled · Ability to send crafted HTTP requests
devstral-2 · analyzed Feb 27, 2026 Full analysis →

Nuclei Templates (1)

Apache mod_userdir CRLF injection
MEDIUMby melbadry9,nadino,xElkomy
Shodan: cpe:"cpe:2.3:a:apache:http_server" || apache 2.4.49

References (24)

Core 24
Core References
Third Party Advisory, VDB Entry vdb-entry x_refsource_bid
http://www.securityfocus.com/bid/105093
Third Party Advisory x_refsource_confirm
https://security.netapp.com/advisory/ntap-20180926-0006/

Scores

CVSS v3 6.1
EPSS 0.1980
EPSS Percentile 97.1%
Attack Vector NETWORK
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Details

CWE
CWE-93
Status published
Products (41)
apache/http_server 2.2.0
apache/http_server 2.2.2
apache/http_server 2.2.3
apache/http_server 2.2.4
apache/http_server 2.2.6
apache/http_server 2.2.8
apache/http_server 2.2.9
apache/http_server 2.2.10
apache/http_server 2.2.11
apache/http_server 2.2.12
... and 31 more
Published Aug 14, 2018
Tracked Since Feb 18, 2026