CVE-2026-73427 Trix: XSS via JSON deserialization bypass in drag-and-drop (Level0InputController)
Attackers can inject JavaScript via crafted JSON drag-and-drop payloads in Trix editor, requiring user interaction to execute code.
- 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-2026-73427?
CVE-2026-73427 is a low-severity cross-site scripting vulnerability in basecamp trix, published on 12 Aug 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
Trix is a what-you-see-is-what-you-get rich text editor for everyday writing. Prior to 2.1.18, Trix is vulnerable to cross-site scripting when a crafted application/x-trix-document JSON payload is dropped into an editor using the fallback Level0InputController, such as an embedded WebView without Input Events Level 2 support. The StringPiece.fromJSON method trusts href attributes from the JSON payload without sanitization, allowing a draggable element containing a javascript: URI to bypass DOMPurify sanitization and inject executable JavaScript into the DOM. Exploitation requires the victim to drag and drop attacker-controlled content, and server-side HTML sanitization can neutralize the payload on save. This issue is fixed in version 2.1.18.
Weakness: CWE-79
Which versions are affected by CVE-2026-73427?
4 open source packages ship an affected version, including action_text-trix and trix.
| Package | Affected | Fixed in |
|---|---|---|
action_text-trix RubyGems | All versions | 2.1.18 |
action_text-trix RubyGems | All versions | 2.1.18 |
trix npm | All versions | 2.1.18 |
trix npm | All versions | 2.1.18 |
How do I fix CVE-2026-73427?
Upgrade action_text-trix to 2.1.18 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-2026-73427 being exploited?
There is no known exploitation of CVE-2026-73427 in the wild and no public exploit code.
Sources
Also known as GHSA-53p3-c7vp-4mcc.