CVE-2016-4975 mod_userdir CRLF injection

What is CVE-2016-4975?

CVE-2016-4975 is a medium-severity vulnerability in Apache Http Server, published on 14 Aug 2018. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official 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).

Weakness: CWE-93

Which versions are affected by CVE-2016-4975?

It affects 1 product.

Products include Apache Http Server.

How do I fix CVE-2016-4975?

Upgrade to a fixed version.

Is CVE-2016-4975 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2016-4975 exists.

Public exploit code: 1 Nuclei template.

Other vulnerabilities in Apache Http Server

• CVE-2021-42013 Apache HTTP Server Path Traversal Exploited Critical 9.8
• CVE-2024-38475 Apache HTTP Server Improper Escaping of Output Exploited Critical 9.1
• CVE-2021-40438 Apache HTTP Server-Side Request Forgery (SSRF) Exploited Critical 9.0
• CVE-2019-0211 Apache HTTP Server Privilege Escalation Exploited High 7.8
• CVE-2021-41773 Apache HTTP Server Path Traversal Exploited High 7.5

All Apache Http Server vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2016-4975, GHSA-crcg-r773-w4rv, UBUNTU-CVE-2016-4975.