Nagios Xi
CVE-2021-47698
MEDIUM
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V1 - Encoding and Sanitization Output encoding, context-aware escaping
MITRE ATT&CK
2 techniques across 2 tactics: Initial Access, Execution The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | CVSS score of 5.1 (MEDIUM). Attack characteristics: network attack vector, low complexity, low privileges required, user interaction required. EPSS exploitation probability: 0.68%. |
| Exploit ScenarioDerived | A remote attacker could inject malicious scripts into web pages viewed by other users by sending crafted requests to the affected application. |
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Alert meAnalysisAIv1 – Mar 28, 2026
Nagios XI versions prior to 5.8.7 using embedded Nagios Core are vulnerable to cross-site scripting (XSS) via the Core UI’s Views URL handling (escape_string()). Rated medium severity (CVSS 5.1), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Earlier versions of this analysis (1)
RemediationAI
No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Sanitize all user input, use Content-Security-Policy headers, encode output contextually (HTML, JS, URL). Use frameworks with built-in XSS protection.
Affects your stack
Find out whether the stacks and servers you run are on an affected version.
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
This vulnerability is classified as Cross-Site Scripting (XSS) (CWE-79), which allows attackers to inject malicious scripts into web pages viewed by other users. Nagios XI versions prior to 5.8.7 using embedded Nagios Core are vulnerable to cross-site scripting (XSS) via the Core UI’s Views URL handling (escape_string()). Insufficient validation or escaping of user-supplied input may allow an attacker to inject and execute arbitrary script in the context of a victim's browser. Affected products include: Nagios Nagios Xi. Version information: prior to 5.8.7.
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
DescriptionCVE.org
Nagios XI versions prior to 5.8.7 using embedded Nagios Core are vulnerable to cross-site scripting (XSS) via the Core UI’s Views URL handling (escape_string()). Insufficient validation or escaping of user-supplied input may allow an attacker to inject and execute arbitrary script in the context of a victim's browser.
Executive ViewAI
CVE-2021-47698 presents moderate security risk, a cross-site scripting vulnerability rated CVSS 5.1. Attackers could inject scripts to steal sessions or perform actions as authenticated users. Organizations should apply vendor updates when available and monitor for exploitation.
Apply vendor patch. If patching is delayed: implement CSP headers, enable HttpOnly cookies, deploy WAF XSS rules.
Threat Intelligence Overview
NVD
CVE.org
EPSS
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Cross-Site Scripting occurs when an application accepts untrusted data and sends it to a web browser without proper validation or encoding.
Affected Products (CPE)CVE.org
Nagios XI version xi-5.7.5 is affected by OS command injection. Rated high severity (CVSS 8.8), this vulnerability is re
Nagios XI version xi-5.7.5 is affected by OS command injection. Rated high severity (CVSS 8.8), this vulnerability is re
Nagios XI version xi-5.7.5 is affected by OS command injection. Rated high severity (CVSS 8.8), this vulnerability is re
Nagios XI version xi-5.7.5 is affected by cross-site scripting (XSS). Rated medium severity (CVSS 6.1), this vulnerabili
Snoopy 1.0 in Nagios XI 5.5.6 allows remote unauthenticated attackers to execute arbitrary commands via a crafted HTTP r
SQL injection vulnerability in the core config manager in Nagios XI 5.2.x through 5.4.x before 5.4.13 allows an attacker
Authentication bypass vulnerability in the core config manager in Nagios XI 5.2.x through 5.4.x before 5.4.13 allows an
A path traversal vulnerability exists in Nagios XI below version 5.8.5 AutoDiscovery component and could lead to post au
Nagios XI before 5.6.6 allows remote command execution as root. Rated high severity (CVSS 8.8), this vulnerability is re
A privilege escalation vulnerability in Nagios XI 5.2.x through 5.4.x before 5.4.13 allows an attacker to leverage an RC
Remote command execution (RCE) vulnerability in Nagios XI 5.2.x through 5.4.x before 5.4.13 allows an attacker to execut
SQL injection vulnerability in functions/prepend_adm.php in Nagios Core Config Manager in Nagios XI before 2012R2.4 allo
GitHub PoC
Exploit-DB