HTTP Headers: A security weakness
HTTP Headers is affected by a security weakness. Exploitation requires at least administrator-level access. The resulting impact depends on how the affected component exposes the vulnerable operation. The published affected range is <= 1.19.2.
- Component
- HTTP Headers
- Plugin slug
http-headers- Affected
- <= 1.19.2
- Safe version
> 1.19.2- Published
- Apr 22, 2026
This CVE was published Apr 22, 2026 and is one of 7 known issues for this plugin.
Update, patch or deactivate.
Update HTTP Headers to a release after 1.19.2, or disable and remove it until a fixed version is available.
A safe version is available, so updating to that version or later is the preferred remediation. If an immediate update is not practical, consider a targeted application patch or temporarily restricting the affected functionality.
Deactivate only when warranted by your risk profile, or when advised by your hosting provider in the limited circumstances where the vulnerability cannot otherwise be mitigated. If you’re unsure which action is appropriate, contact Fused or your hosting provider for guidance.
Technical 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.
CVE / CNA vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:L/A:H