HTTP Headers, CVE-2026-2717

CVE, Research URL: CVE-2026-2717
Home page URL: Security reports for HTTP Headers
Application: HTTP Headers
Published on: Apr 22, 2026
Research 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.
Affected versions: max 1.19.2.
Status: vulnerable