CVE-2025-21610

The Trix editor, versions prior to 2.1.11, is vulnerable to XSS when pasting malicious code in the link field.

Workarounds

This is not really a workaround but something that should be considered in addition to upgrading to the patched version. If affected users can disallow browsers that don't support a Content Security Policy, then this would be an effective workaround for this and all XSS vulnerabilities. Set CSP policies such as script-src 'self' to ensure that only scripts hosted on the same origin are executed, and explicitly prohibit inline scripts using script-src-elem.

References

https://gist.github.com/th4s1s/3921fd9c3e324ad9a3e0d846166e3eb8

Credits

This vulnerability was reported by Hackerone researcher https://hackerone.com/lio346?type=user

An attacker could trick the user to copy&paste a malicious javascript: URL as a link that would execute arbitrary JavaScript code within the context of the user's session, potentially leading to unauthorized actions being performed or sensitive information being disclosed.

See https://gist.github.com/th4s1s/3921fd9c3e324ad9a3e0d846166e3eb8

Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.

CVE-2025-21610 has a CVSS score of 5.3 (Medium). The vector is network-reachable, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (2.1.12); upgrading removes the vulnerable code path.

Kodem intelligence

Update Recommendation: Users should upgrade to Trix editor version 2.1.12 or later.

1. What is CVE-2025-21610? CVE-2025-21610 is a medium-severity cross-site scripting (XSS) vulnerability in trix (npm), affecting versions < 2.1.12. It is fixed in 2.1.12. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
2. How severe is CVE-2025-21610? CVE-2025-21610 has a CVSS score of 5.3 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of trix are affected by CVE-2025-21610? trix (npm) versions < 2.1.12 is affected.
4. Is there a fix for CVE-2025-21610? Yes. CVE-2025-21610 is fixed in 2.1.12. Upgrade to this version or later.
5. Is CVE-2025-21610 exploitable, and should I be worried? Whether CVE-2025-21610 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2025-21610 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2025-21610? Upgrade trix to 2.1.12 or later.