CVE-2026-73426 Trix: Stored XSS vulnerability through serialized attributes
Attackers can execute arbitrary JavaScript in user sessions via malicious serialized attributes in the Trix rich text editor library.
- 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-2026-73426?
CVE-2026-73426 is a medium-severity cross-site scripting vulnerability in basecamp trix, published on 18 Aug 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
Trix is a what-you-see-is-what-you-get rich text editor for everyday writing. Prior to 2.1.17, Trix is vulnerable to cross-site scripting when a data-trix-serialized-attributes attribute bypasses the DOMPurify sanitizer. An attacker can craft HTML containing a data-trix-serialized-attributes attribute with a malicious payload that, when rendered, executes arbitrary JavaScript in the user's session and may perform unauthorized actions or disclose sensitive information. This issue is fixed in version 2.1.17.
Weakness: CWE-79
Which versions are affected by CVE-2026-73426?
4 open source packages ship an affected version, including action_text-trix and trix.
| Package | Affected | Fixed in |
|---|---|---|
action_text-trix RubyGems | All versions | 2.1.17 |
action_text-trix RubyGems | All versions | 2.1.17 |
trix npm | All versions | 2.1.17 |
trix npm | All versions | 2.1.17 |
How do I fix CVE-2026-73426?
Upgrade action_text-trix to 2.1.17 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-2026-73426 being exploited?
There is no known exploitation of CVE-2026-73426 in the wild and no public exploit code.
Sources
Also known as GHSA-qmpg-8xg6-ph5q.