Vulnerability in Zinoui HTTP Headers
CVE-2026-2717
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.
Vulnerability class: CRLF Injection
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:L/A:H.
EPSS exploit prediction
EPSS: 0.006 (44.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 45th percentile — 44.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.006 · change: +0.001
Affected products
- Zinoui HTTP Headers — versions 0
Weakness classification (CWE)
References
- www.wordfence.com/threat-intel/vulnerabilities/id/7716e77f-e899-4046-9421-86fc0…
- plugins.trac.wordpress.org/browser/http-headers/tags/1.19.2/http-headers.php
- plugins.trac.wordpress.org/browser/http-headers/trunk/http-headers.php
- plugins.trac.wordpress.org/browser/http-headers/tags/1.19.2/http-headers.php
- plugins.trac.wordpress.org/browser/http-headers/trunk/http-headers.php
Frequently asked questions
- What is CVE-2026-2717?
- CVE-2026-2717 is a medium-severity vulnerability in Zinoui HTTP Headers, classified under CRLF Injection. CVSS score: 5.5/10. Published 2026-04-22.
- How severe is CVE-2026-2717?
- Medium severity. CVSS v3 base score is 5.5 out of 10.