XSS in Wssoffice21 Ymc Filter

CVE-2026-109983

The YMC Filter plugin for WordPress is vulnerable to Stored DOM-Based Cross-Site Scripting via the 'post_title' parameter in all versions up to, and including, 3.12.19 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with author-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The autocomplete REST endpoint is registered with a permission callback that unconditionally returns true, meaning any site visitor — including unauthenticated users — can trigger the payload simply by typing in the YMC filter search box, while only Author-level access is required to store it.

Vulnerability class: XSS (Cross-Site Scripting)

Published .

CVSS v3 metric

CVSS v3 base score 6.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-109983?
CVE-2026-109983 is a medium-severity vulnerability in Wssoffice21 Ymc Filter, classified under Cross-site Scripting. CVSS score: 6.4/10. Published 2026-10-17.
How severe is CVE-2026-109983?
Medium severity. CVSS v3 base score is 6.4 out of 10.