What the vulnerability does
01Description
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.
Explanation of Vulnerability in Simple Terms
02Summary
The HTTP Headers component in zinoui versions up to 1.19.2 contains an improper input validation flaw that allows authenticated administrators to modify HTTP response headers in ways that degrade service availability or corrupt response integrity. The vulnerability requires high-level privileges and does not expose confidential data. A patch version has not been publicly identified.
What an attacker can do
03Attacker Capabilities
An authenticated admin can manipulate HTTP headers to disrupt site availability or corrupt responses.
Potential impact on your site
04Site Impact
Admins with compromised credentials could degrade site performance or corrupt HTTP responses sent to visitors.
Conditions required to exploit
05Prerequisites
Attacker must have administrator-level access to the affected component.
Key dates
06Disclosure timeline
April 22, 2026
CVE published
April 22, 2026
Record updated
