CVE-2026-56383
CVE-2026-56383 is a Cross-site Scripting (XSS) vulnerability in craftcms/cms. O3 Security confirms whether CVE-2026-56383 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Craft CMS - Stored XSS in Table Field via Row Heading Column Type
Blast Radius
craftcms/cms🐘craftcms/cmsReal-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
Craft CMS contains a stored cross-site scripting (XSS) vulnerability in the editableTable.twig component when using the 'Row Heading' column type. The application fails to sanitize input within row heading default values, allowing an attacker with an administrator account (with allowAdminChanges enabled) to inject arbitrary JavaScript that executes when another user views a page containing the affected table field. Affected versions are >= 4.5.0-beta.1 through 4.16.18 and >= 5.0.0-RC1 through 5.8.22; fixed in 4.16.19 and 5.8.23.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | craftcms/cms | ≥ 4.5.0-beta.1&&< 4.16.19 | 4.16.19 |
| 🐘Packagist | craftcms/cms | ≥ 5.0.0-RC1&&< 5.8.23 | 5.8.23 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for craftcms/cms. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update craftcms/cms to 4.16.19 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-56383 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-56383 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-56383. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-56383 in your dependencies?
O3 detects CVE-2026-56383 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.