What is CVE-2018-20172?

CVE-2018-20172 is a medium-severity vulnerability in Nagios Xi, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2018-12-17.

How severe is CVE-2018-20172?

Medium severity. CVSS v3 base score is 6.1 out of 10.

XSS in Nagios Xi

CVE-2018-20172

An issue was discovered in Nagios XI before 5.5.8. The rss_url parameter of rss_dashlet/magpierss/scripts/magpie_slashbox.php is not filtered, resulting in an XSS vulnerability.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2018-12-17 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.016 (74.6th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 75th percentile — 74.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.016 · newest: 0.016 · change: 0.000

Affected products

Nagios Xi

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

www.nagios.com/downloads/nagios-xi/change-log/ (Vendor Advisory)
www.seebug.org/vuldb/ssvid-97714 (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2018-20172?: CVE-2018-20172 is a medium-severity vulnerability in Nagios Xi, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2018-12-17.
How severe is CVE-2018-20172?: Medium severity. CVSS v3 base score is 6.1 out of 10.