XSS in Sproutient Zypento Blocks

CVE-2026-5820

The Zypento Blocks plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the Table of Contents block in all versions up to, and including, 1.0.6. This is due to the front-end TOC rendering script reading heading text via `innerText` and inserting it into the page using `innerHTML` without proper sanitization. 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.

Vulnerability class: XSS (Cross-Site Scripting)

Published · last modified .

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

EPSS: 0.003 (22.9th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 23rd percentile — 22.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-5820: held from 0.002 to 0.003.

EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-5820?
CVE-2026-5820 is a medium-severity vulnerability in Sproutient Zypento Blocks, classified under Cross-site Scripting. CVSS score: 6.4/10. Published 2026-04-22.
How severe is CVE-2026-5820?
Medium severity. CVSS v3 base score is 6.4 out of 10.