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Public proof of conceptFix available

CVE-2021-38156

A public proof of concept exists; no exploitation attested.

  • Published2021-09-15
  • Fixed in5.8.6
  • WeaknessCWE-79

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

In Nagios XI before 5.8.6, XSS exists in the dashboard page (/dashboards/#) when administrative users attempt to edit a dashboard.

Timeline

dates in UTC
  1. 2021-09-1514:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-11-03 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-38156?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-38156?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Nagios nagios xi
BranchAffectedFixed in
5.8< 5.8.65.8.6

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

  1. Update Nagios nagios xi to 5.8.6

Advisories and patches

Detection

read 2026-11-03 22:42 UTC
Nuclei template
available
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub
Metasploit modules
none listed
Metasploit Framework

Sources

  • NVDCVSS 3.15.4read 2026-10-23
  • NVDCVSS 2.03.5read 2026-10-23
  • NVDweakness (CWE)CWE-79read 2026-10-23
  • FIRST EPSSEPSS score92.9 %read 2026-11-03
  • ProjectDiscoverydetectionread 2026-11-03

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Published
2021-09-15
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is CVE-2021-38156?

In Nagios XI before 5.8.6, XSS exists in the dashboard page (/dashboards/#) when administrative users attempt to edit a dashboard.

Is CVE-2021-38156 actively exploited?

Active exploitation of CVE-2021-38156 has not been confirmed. Its EPSS score was 92.9% on 2026-11-03, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-38156?

CVE-2021-38156 has a CVSS v3 base score of 5.4 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N.

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