XSS in Humhub Calendar
CVE-2026-29052
The Calendar module for HumHub enables users to create one-time or recurring events, manage attendee invitations, and efficiently track all scheduled activities. Prior to version 1.8.11, a Stored Cross-Site Scripting (XSS) vulnerability in the Event Types of the HumHub Calendar module impacts users viewing events created by an administrative account. This issue has been patched in version 1.8.11.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.003 (17.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 18th percentile — 17.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001
Affected products
- Humhub Calendar — versions < 1.8.11
Weakness classification (CWE)
References
- github.com/humhub/calendar/security/advisories/GHSA-gqj3-pmp2-mrx8 (Mitigation, Vendor Advisory)
- github.com/humhub/calendar/releases/tag/v1.8.11 (Product, Release Notes)
Frequently asked questions
- What is CVE-2026-29052?
- CVE-2026-29052 is a medium-severity vulnerability in Humhub Calendar, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-03-05.
- How severe is CVE-2026-29052?
- Medium severity. CVSS v3 base score is 6.1 out of 10.