What is CVE-2017-16906?

CVE-2017-16906 is a medium-severity vulnerability in Horde Groupware, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2017-11-20.

How severe is CVE-2017-16906?

Medium severity. CVSS v3 base score is 5.4 out of 10.

XSS in Horde Groupware

CVE-2017-16906

In Horde Groupware 5.2.19-5.2.22, there is XSS via the URL field in a "Calendar -> New Event" action.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2017-11-20 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.011 (63.9th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 64th percentile — 63.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.011 · newest: 0.011 · change: 0.000

Affected products

Horde Groupware

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

code610.blogspot.com/2017/11/rce-via-xss-horde-5219.html (Exploit, Third Party Advisory, Issue Tracking)
github.com/horde/kronolith/commit/09d90141292f9ec516a7a2007bf828ce2bbdf60d (Patch, Third Party Advisory)
github.com/starnightcyber/Miscellaneous/blob/master/Horde/README.md (Exploit, Third Party Advisory)
lists.debian.org/debian-lts-announce/2020/08/msg00049.html (mailing-list)

Frequently asked questions

What is CVE-2017-16906?: CVE-2017-16906 is a medium-severity vulnerability in Horde Groupware, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2017-11-20.
How severe is CVE-2017-16906?: Medium severity. CVSS v3 base score is 5.4 out of 10.