CVE-2026-2717 HTTP Headers <= 1.19.2 - Authenticated (Administrator+) CRLF Injection via Custom Header Values
Administrators can inject CRLF characters into Apache configuration files via custom headers, causing parse errors and site-wide denial of service.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-2717?
CVE-2026-2717 is a medium-severity vulnerability in zinoui HTTP Headers, published on 22 Apr 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Official 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.
Weakness: CWE-93
Which versions are affected by CVE-2026-2717?
How do I fix CVE-2026-2717?
No fix has been published for CVE-2026-2717 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-2717 being exploited?
There is no known exploitation of CVE-2026-2717 in the wild and no public exploit code.
Sources
Also known as GHSA-r256-59w3-3gr2.