CVE-2026-55596 Plate: Media embed provider metadata can bypass URL sanitization and execute iframe JavaScript
Attackers can execute arbitrary JavaScript in victims' browsers by crafting documents that bypass URL sanitization in the media embed renderer.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-55596?
CVE-2026-55596 is a high-severity cross-site scripting vulnerability in udecode plate, published on 8 Jul 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
Plate is a rich-text editor with AI and shadcn/ui. From 53.0.0 until 53.1.4, the media embed renderer trusts serialized provider or sourceUrl metadata in useMediaState and skips parseMediaUrl protocol validation, allowing a crafted Plate document to set a known video provider while keeping url as a javascript: iframe source that the registry MediaEmbedElement renders directly as an iframe src when a victim opens the document. This issue is fixed in version 53.1.4.
Weakness: CWE-79
Which versions are affected by CVE-2026-55596?
2 open source packages ship an affected version, including @platejs/media.
| Package | Affected | Fixed in |
|---|---|---|
@platejs/media npm | From 53.0.0 | 53.1.4 |
@platejs/media npm | From 53.0.0 | 53.1.4 |
How do I fix CVE-2026-55596?
Upgrade @platejs/media to 53.1.4 or later.
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-2026-55596 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55596 exists.
Sources
Also known as GHSA-qj6x-xx2h-8hvv.