CVE-2026-104021Fastcache by Host.it <= 1.7.4 - Authenticated (Administrator+) Code Injection via .htaccess Directive Injection via 'cache_cookie_exclude' Setting

The Fastcache by Host.it plugin for WordPress is vulnerable to Code Injection in all versions up to, and including, 1.7.4 via the `fastcache_settings[cache_cookie_exclude][]` parameter. This is due to the plugin registering the `cache_cookie_exclude` setting via `register_setting()` without a `sanitize_callback`, while `buildSiteHtaccessRules()` applies only `trim()` to each cookie value before interpolating it directly into an Apache `RewriteCond` line — a normalization that strips surrounding whitespace but leaves embedded newlines intact, allowing an attacker to break out of the capture group and append arbitrary directives. This makes it possible for authenticated attackers, with administrator-level access and above, to inject arbitrary Apache directives into the site's `.htaccess` file via `file_put_contents()`, enabling server-level configuration changes such as setting `php_value auto_prepend_file` to execute attacker-controlled PHP code on every request.

CVSS

7.2 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Weakness (CWE)

CWE-94

Known exploited

Not in CISA's KEV catalog

EPSS (exploitation in the next 30 days)

0.40% (percentile 33)

Assigned by

Wordfence

NVD analysis

Deferred

Record last updated

Oct 11, 2026

First seen by InfoSec Signals

Oct 10, 2026

The CVE record on cve.org · NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.