6.1Medium
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.
What this means for your business
- It affects Humhub Calendar. It matters if your company, or a supplier that handles your data, runs it.
- An attacker can use it remotely, over a network, without a login, but only after tricking someone into an action such as opening a file or a link.
- FIRST's prediction model gives it a 0.2% chance of attack attempts being seen in the next 30 days, ranking above 5% of all known flaws.
What to do
- 1Check whether your company or your suppliers run Humhub Calendar, and which version. The affected versions are listed further down this page.
- 2If you do, apply the vendor's fix. A patch or vendor advisory has been published.
Not sure if your company is exposed?
Fastnexa’s certified penetration testers can check whether attackers could use this flaw, or others like it, against your websites, apps and network. The full test is free for our first 10 founding clients until 31 December 2026.
Scoring
- CVSS
- 6.1 (v3.1)
- Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N- CVSS v4
- 6.9
- Weakness
- CWE-79
- Assigned by
- security-advisories@github.com
Dates
- Published
- 2026-03-05
- Last modified
- 2026-09-02
- Sources
- NVD
Affected products
- Humhub Calendar- 1.8.11
As listed in the NVD configuration data. Not a statement about your estate.