What is CVE-2026-12900?

CVE-2026-12900 is a medium-severity vulnerability in Brainstormforce Spectra Legacy – Gutenberg Blocks, classified under Cross-site Scripting. CVSS score: 6.4/10. Published 2026-07-20.

How severe is CVE-2026-12900?

Medium severity. CVSS v3 base score is 6.4 out of 10.

XSS in Brainstormforce Spectra Legacy – Gutenberg Blocks

CVE-2026-12900

The Spectra Gutenberg Blocks – Website Builder for the Block Editor plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the `uagb/image` block in all versions up to, and including, 2.19.28 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with Contributor-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)

EPSS: 0.003 (24.6th percentile) — read the EPSS interpretation.

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.

Affected products

Brainstormforce Spectra Legacy – Gutenberg Blocks — versions 0

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

Frequently asked questions

What is CVE-2026-12900?: CVE-2026-12900 is a medium-severity vulnerability in Brainstormforce Spectra Legacy – Gutenberg Blocks, classified under Cross-site Scripting. CVSS score: 6.4/10. Published 2026-07-20.
How severe is CVE-2026-12900?: Medium severity. CVSS v3 base score is 6.4 out of 10.