---
id: CVE-2026-104021
title: >-
  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
summary: >-
  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_co…
severity: high
cvss: 7.2
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-94
published: '2026-10-10'
updated: '2026-10-10'
sourceUpdated: '2026-10-10T05:16:39.503'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-104021'
references:
  - url: >-
      https://plugins.trac.wordpress.org/browser/fastcache-by-host-it/tags/1.7.4/src/Admin.php#L73
    label: security@wordfence.com
  - url: >-
      https://plugins.trac.wordpress.org/browser/fastcache-by-host-it/tags/1.7.4/src/Core/Platform/Utility.php#L420
    label: security@wordfence.com
  - url: >-
      https://plugins.trac.wordpress.org/browser/fastcache-by-host-it/tags/1.7.4/src/Core/Platform/Utility.php#L521
    label: security@wordfence.com
  - url: >-
      https://plugins.trac.wordpress.org/browser/fastcache-by-host-it/tags/1.7.4/src/Core/Platform/Utility.php#L545
    label: security@wordfence.com
  - url: >-
      https://plugins.trac.wordpress.org/browser/fastcache-by-host-it/tags/1.7.4/src/Dispatcher.php#L480
    label: security@wordfence.com
  - url: >-
      https://plugins.trac.wordpress.org/changeset?reponame=&old=3735944%40fastcache-by-host-it&new=3735944%40fastcache-by-host-it
    label: security@wordfence.com
  - url: >-
      https://www.wordfence.com/threat-intel/vulnerabilities/id/d72d7a21-0bea-4a32-b92b-326f47998b80?source=cve
    label: security@wordfence.com
tags:
  - nvd
ingestedAt: '2026-10-10T05:23:33.491Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.