Description
The HTTP Headers plugin for WordPress is vulnerable to CRLF Injection in all versions up to, and including, 1.19.2. This is due to insufficient sanitization of custom header name and value fields before writing them to the Apache .htaccess file via `insert_with_markers()`. This makes it possible for authenticated attackers, with Administrator-level access and above, to inject arbitrary newline characters and additional Apache directives into the .htaccess configuration file via the 'Custom Headers' settings, leading to Apache configuration parse errors and potential site-wide denial of service.
References5
- plugins.trac.wordpress.org/browser/http-headers/tags/1.19.2/htt…
- plugins.trac.wordpress.org/browser/http-headers/tags/1.19.2/htt…
- plugins.trac.wordpress.org/browser/http-headers/trunk/http-head…
- plugins.trac.wordpress.org/browser/http-headers/trunk/http-head…
- www.wordfence.com/threat-intel/vulnerabilities/id/7716e77f-e899…
Metrics
- CVSS 3.1
-
5.5
MEDIUM
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:L/A:H - EPSS — exploit probability
- 0% percentile: 42 · as of 13 November 2026
- CWE
- CWE-93
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.