CVE-2026-4139 mCatFilter <= 0.5.2 - Cross-Site Request Forgery via compute_post() Function
Unauthenticated attackers can modify plugin settings via CSRF if an administrator clicks a malicious link.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-4139?
CVE-2026-4139 is a medium-severity vulnerability in chsxf mCatFilter, published on 22 Apr 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
The mCatFilter plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to and including 0.5.2. This is due to the complete absence of nonce verification and capability checks in the compute_post() function, which processes settings updates. The compute_post() function is called in the plugin constructor on every page load via the plugins_loaded hook, and it directly processes $_POST data to modify plugin settings via update_option() without any CSRF token validation. This makes it possible for unauthenticated attackers to modify all plugin settings, including category exclusion rules, feed exclusion flags, and tag page exclusion flags, via a forged POST request, granted they can trick a site administrator into performing an action such as clicking a link.
Weakness: CWE-352
Which versions are affected by CVE-2026-4139?
How do I fix CVE-2026-4139?
No fix has been published for CVE-2026-4139 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-4139 being exploited?
There is no known exploitation of CVE-2026-4139 in the wild and no public exploit code.
Sources
Also known as GHSA-9p67-72c6-m54h.