CVE-2026-104847 ProseMirror: XSS vulnerability in prosemirror-view's paste handling
Attackers can execute arbitrary JavaScript in a user's browser by crafting HTML with unvalidated attributes that bypass schema validation during paste operations in ProseMirror editors.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-104847?
CVE-2026-104847 is a high-severity cross-site scripting vulnerability in prosemirror-view, published on 2 Oct 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
ProseMirror's view component renders and manages the editable browser interface for ProseMirror documents. Prior to 1.42.3, prosemirror-view paste handling accepts attacker-provided HTML whose clipboard slice context contains attributes that are not passed through schema attribute validation. When a user pastes the crafted HTML into an editor, the unvalidated context attributes can construct content that executes attacker-controlled JavaScript in the browser window containing the editor. This issue is fixed in version 1.42.3.
Weakness: CWE-79
Which versions are affected by CVE-2026-104847?
2 open source packages ship an affected version, including prosemirror-view.
| Package | Affected | Fixed in |
|---|---|---|
prosemirror-view npm | All versions | 1.42.3 |
prosemirror-view npm | All versions | 1.42.3 |
How do I fix CVE-2026-104847?
Upgrade prosemirror-view to 1.42.3 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-2026-104847 being exploited?
There is no known exploitation of CVE-2026-104847 in the wild and no public exploit code.
Sources
Also known as ECHO-6adb-f707-8d52, GHSA-c8x8-7fp4-3x9w, MINI-2x3r-qwf7-m9mx, ROOT-APP-NPM-CVE-2026-104847.