CVE-2026-84899 VikWidgetsLoader < 1.12.0 - Contributor+ Stored XSS via Gutenberg Block class_suffix
Contributors can inject JavaScript via Gutenberg block attributes, leading to code execution in admin browsers and potential account takeover.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-84899?
CVE-2026-84899 is a medium-severity cross-site scripting vulnerability in Unknown VikWidgetsLoader, published on 5 Sep 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.
Official description
The VikWidgetsLoader WordPress plugin before 1.12.0 does not sanitise or escape a block attribute before outputting it inside an inline script, allowing users with the Contributor role to store arbitrary JavaScript that executes in the browser of any user viewing the affected post, including the administrator who reviews the pending submission.
Weakness: CWE-79
Which versions are affected by CVE-2026-84899?
How do I fix CVE-2026-84899?
No fix has been published for CVE-2026-84899 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-2026-84899 being exploited?
There is no known exploitation of CVE-2026-84899 in the wild and no public exploit code.
Sources
Also known as GHSA-gff8-vmj9-6526.