CVE-2026-12399 — jegstudio Vulnerability

What is CVE-2026-12399?

The Gutenverse – WordPress Blocks, Page Builder & Site Editor plugin for WordPress is vulnerable to Stored Cross-Site Scripting via admin settings in all versions up to, and including, 3.8.0 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with editor-level permissions and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This only affects multi-site installations and installations where unfiltered_html has been disabled.

The record classifies CVE-2026-12399 under weakness class CWE-79. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs high-privilege credentials, needs no user interaction. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 100 days ago.

Severity and exploitation probability

CVSS v3.1 base score: 4.4 — MEDIUM
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:L/I:L/A:N
EPSS (FIRST): 0.2% probability of exploitation in the next 30 days, higher than 15.7% of all scored CVEs
CISA KEV: Not listed in the CISA Known Exploited Vulnerabilities catalog
Threadlinqs priority: 2.8/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
Published: 2026-06-27

Is CVE-2026-12399 being exploited?

It currently carries a trending score of 33 in the Threadlinqs vulnerability feed.

Affected products and versions

jegstudio: Gutenverse – WordPress Blocks, Page Builder & Site Editor

How to fix CVE-2026-12399

No vendor patch reference has been recorded for CVE-2026-12399 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

Threat activity tracking CVE-2026-12399

No threat campaign in the Threadlinqs corpus currently references CVE-2026-12399, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.

Sources

Enriched from CVE.org, NVD, FIRST EPSS, GitHub Security Advisories. Last verified by Threadlinqs on 2026-06-29. This product uses the NVD API but is not endorsed or certified by the NVD.

Other references

Showing 5 of 12 recorded references.

CVE-2026-12399 — jegstudio Gutenverse – WordPress Blocks, Page Builder & Site Editor