medium
6.1
CWE
93
Advisory Published
Updated

CVE-2016-4975: mod_userdir CRLF injection

First published: Tue Aug 14 2018(Updated: )

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).

Credit: security@apache.org

Affected SoftwareAffected VersionHow to fix
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
Apache Http Server=2.2.13
Apache Http Server=2.2.14
Apache Http Server=2.2.15
Apache Http Server=2.2.16
Apache Http Server=2.2.17
Apache Http Server=2.2.18
Apache Http Server=2.2.19
Apache Http Server=2.2.20
Apache Http Server=2.2.21
Apache Http Server=2.2.22
Apache Http Server=2.2.23
Apache Http Server=2.2.24
Apache Http Server=2.2.25
Apache Http Server=2.2.26
Apache Http Server=2.2.27
Apache Http Server=2.2.29
Apache Http Server=2.2.31
Apache Http Server=2.4.1
Apache Http Server=2.4.2
Apache Http Server=2.4.3
Apache Http Server=2.4.4
Apache Http Server=2.4.6
Apache Http Server=2.4.7
Apache Http Server=2.4.9
Apache Http Server=2.4.10
Apache Http Server=2.4.12
Apache Http Server=2.4.16
Apache Http Server=2.4.17
Apache Http Server=2.4.18
Apache Http Server=2.4.20
Apache Http Server=2.4.23

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Reference Links

Frequently Asked Questions

  • What is the severity of CVE-2016-4975?

    CVE-2016-4975 has a medium severity rating that permits potential HTTP response splitting attacks due to CRLF injection.

  • How do I fix CVE-2016-4975?

    To fix CVE-2016-4975, upgrade to Apache HTTP Server version 2.4.25 or later for 2.4.x versions, or 2.2.32 or later for 2.2.x versions.

  • Who is affected by CVE-2016-4975?

    CVE-2016-4975 affects Apache HTTP Server versions 2.2.0 through 2.2.31 and versions 2.4.0 through 2.4.23.

  • What is a CRLF injection as mentioned in CVE-2016-4975?

    CRLF injection refers to the exploitation of carriage return and line feed characters in HTTP requests which can lead to header manipulation.

  • When was CVE-2016-4975 discovered?

    CVE-2016-4975 was disclosed in 2016 and allowed for potential exploitation of certain Apache HTTP Server configurations.

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