CVE-2026-12399 Gutenverse <= 3.8.0 - Authenticated (Editor+) Stored Cross-Site Scripting via 'fonts[].font.font.value' Parameter
Authenticated editors can inject arbitrary scripts via font settings in Gutenverse, affecting multi-site or restricted HTML installations.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-12399?
CVE-2026-12399 is a medium-severity cross-site scripting vulnerability in jegstudio Gutenverse – WordPress Blocks, Page Builder & Site Editor, published on 27 Jun 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Official description
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.
Weakness: CWE-79
Which versions are affected by CVE-2026-12399?
How do I fix CVE-2026-12399?
No fix has been published for CVE-2026-12399 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-2026-12399 being exploited?
There is no known exploitation of CVE-2026-12399 in the wild and no public exploit code.
Sources
Also known as GHSA-pgr2-vvf9-xmqw.