6.1

CVE-2021-25299: nagios nagios_xi Cross-site Scripting

CVSS: 6.1v3.1MediumModified
Published 15-02-2021Last modified 09-07-2026
Open JSON

Vulnerability summary

CVE-2021-25299 is a medium (CVSS 6.1) Cross-site Scripting vulnerability in nagios nagios_xi. EPSS estimates a 97.76% chance of exploitation in the next 30 days, higher than 99.9% of scored vulnerabilities. 2 public exploits are recorded.

Overall risk
54/100
0100
High · default modelHow is this calculated?
CVSS score
6.1/10
010
Medium · v3.1 (NVD)
EPSS score
97.76%
0%100%
Critical · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits2github, reference

Timeline

  1. 15-02-2021
    PublishedVulnerability first disclosed.
  2. 09-07-2026
    Last modifiedVulnerability information updated.

Description

Nagios XI version xi-5.7.5 is affected by cross-site scripting (XSS). The vulnerability exists in the file /usr/local/nagiosxi/html/admin/sshterm.php due to improper sanitization of user-controlled input. A maliciously crafted URL, when clicked by an admin user, can be used to steal his/her session cookies or it can be chained with the previous bugs to get one-click remote command execution (RCE) on the Nagios XI server.

CVSS metrics

2 scores · 1 source · 2 versions

EPSS trend

Probability

97.76%

Chance of exploitation in the next 30 days

Percentile

100%

Versus all other CVEs

30-day change

0.00 pp

From 97.76% on 22-09-2026

22-09-202622-10-2026
EPSS score
97.76%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

2 found
  • githubUnverified

    Nagios Xi 5.7.5 Bugs

    Maturity: poc

  • referenceUnverified

    Exploit Reference (packetstormsecurity.com)

    Maturity: unknown

Weaknesses

CWE · root cause

Affected systems

Nagios1 product

1 vendor · 1 product

References

3 links