CVE-2021-47691Network attack vectorHinoki check available

Authenticated script execution via unescaped service fields

Published Oct 30, 2025 · Updated Oct 30, 2025

Stored XSS in Nagios XI before 5.8.2 allows remote authenticated users to execute script in another user's browser through CCM Services. The Services page stores config_name and service_description input without sufficient validation or output escaping before rendering it in the Core Config Manager. A low-privileged account can plant the payload, but another user must open the affected CCM view; execution is confined to that user's browser context.

CVSS severity5.1
Medium
EPSS probability0.42%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Stored XSS in Nagios XI before 5.8.2 allows remote authenticated users to execute script in another user's browser through CCM Services. The Services page stores config_name and service_description input without sufficient validation or output escaping before rendering it in the Core Config Manager. A low-privileged account can plant the payload, but another user must open the affected CCM view; execution is confined to that user's browser context.

The record

CVE
CVE-2021-47691
Published
Oct 30, 2025
Updated
Oct 30, 2025
Vendor
Nagios Enterprises, LLC
Product
Nagios XI
Classifications
CWE-79, T1203
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 30, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 30, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <5.8.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Nagios Enterprises, LLC · Nagios XIversion=0 <5.8.2

Published CVSS scores

5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
5.1VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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