Calendar event fields permit contributor stored XSS
Calendar before 1.3.18 lets a Contributor place attacker-controlled markup in an event field that the plugin later renders inside an HTML attribute on a public page. The stored payload executes in the browser of a visitor who views the affected event, including a logged-in administrator. The CNA record does not identify the event field, submission action, parameter or rendering function.
- Component
- Calendar
- Plugin slug
calendar- Affected
- < 1.3.18
- Safe version
1.3.18- Published
- Jul 27, 2026
This CVE was published Jul 27, 2026 and is one of 5 known issues for this plugin.
Update, patch or deactivate.
Update Calendar to 1.3.18 or later. Review Contributor-authored events for unexpected markup and remove untrusted event content before administrators or visitors view it.
A safe version is available, so updating to that version or later is the preferred remediation. If an immediate update is not practical, consider a targeted application patch or temporarily restricting the affected functionality.
Deactivate only when warranted by your risk profile, or when advised by your hosting provider in the limited circumstances where the vulnerability cannot otherwise be mitigated. If you’re unsure which action is appropriate, contact Fused or your hosting provider for guidance.
Technical description
The Calendar WordPress plugin before 1.3.18 does not properly escape a user-supplied event field before outputting it inside an HTML attribute on a public-facing page, allowing users with the Contributor role to inject arbitrary JavaScript that executes in the browser of anyone viewing the calendar.
CVE / CNA vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:H