Skip to content
Fencer Intel
high 7.2

CVE-2026-104021 json

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

published 30d ago modified 27d ago also EUVD-2026-96068

cvss
7.2
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 33%
public exploits
0
none known

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_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.

Is CVE-2026-104021 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
29d ago

Exploit prediction

0.39% chance of exploitation in the next 30 days, higher than 33% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 7.2 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Affected products

  • hostspa Fastcache by Host.it

Classification

Weakness
  • CWE-94 Improper Control of Generation of Code
Technology feeds

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.