CVE-2026-55409 is a high-severity (CVSS 7.6) Cross-site Scripting (XSS) vulnerability in filament/forms. A fix is available for filament/forms — see the affected versions and patch details below.
Filament: Disabled RichEditor field state can be used for XSS
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-55409.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-55409 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 379,842 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
filament/formsReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
In Filament v3, a disabled RichEditor field rendered its raw state without sanitizing HTML. Where the data stored in this field's state isn't sanitized already when the form state was filled, an attacker could plant malicious HTML or JavaScript and achieve XSS that executes for users who view the form.
Please note that Filament v4 and above does not use the same mechanism for rendering a disabled RichEditor so this advisory does not apply.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | filament/forms | ≥ 3.0.0&&< 3.3.53 | 3.3.53composer require filament/forms:^3.3.53 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for filament/forms, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update filament/forms to 3.3.53 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-55409 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.
Frequently Asked Questions
Is CVE-2026-55409 in your dependencies?
Find it across Packagist, including transitive dependencies.