CVE-2026-16558 YMC Filter < 3.12.8 - Contributor+ Stored XSS via Layout Builder Schema
Contributors can inject malicious JavaScript into YMC Filter settings, leading to stored XSS attacks against site visitors.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-16558?
CVE-2026-16558 is a medium-severity cross-site scripting vulnerability in Unknown YMC Filter, published on 8 Aug 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
The YMC Filter WordPress plugin before 3.12.8 does not sanitize and escape a layout builder setting before outputting it on a public endpoint, and does not verify object ownership when the setting is saved, allowing users with the Contributor role and above to store JavaScript that executes in the browser of any visitor viewing an affected filter.
Weakness: CWE-79
Which versions are affected by CVE-2026-16558?
How do I fix CVE-2026-16558?
No fix has been published for CVE-2026-16558 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-16558 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-16558 exists.
Sources
Also known as GHSA-p3q7-6w8f-v63h.