CVE-2020-36867
Published: 30 October 2025
Summary
CVE-2020-36867 is a high-severity OS Command Injection (CWE-78) vulnerability in Nagios Nagios Xi. Its CVSS base score is 8.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 20.9% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-2 (Flaw Remediation).
Threat & Defense at a Glance
Threat & Defense Details
Mitigating Controls (NIST 800-53 r5)AI
Directly addresses the command injection by requiring validation and sanitization of user-supplied values before passing to the PDF generation pipeline or shell utilities.
Ensures timely remediation of the specific flaw through patching Nagios XI to version 5.7.3 or later, eliminating the insufficient validation.
Restricts user inputs in PDF export to safe types and formats, reducing opportunities for injecting shell metacharacters or arguments.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
CVE enables remote exploitation of a public-facing web application (Nagios XI) via authenticated command injection, directly facilitating T1190 and arbitrary Unix shell command execution (T1059.004).
NVD Description
Nagios XI versions prior to 5.7.3 contain a command injection vulnerability in the report PDF download/export functionality. User-supplied values used in the PDF generation pipeline or the wrapper that invokes offline/pdf helper utilities were insufficiently validated or improperly escaped, allowing…
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an authenticated attacker who can trigger PDF exports to inject shell metacharacters or arguments.
Deeper analysisAI
CVE-2020-36867 is a command injection vulnerability (CWE-78) affecting Nagios XI versions prior to 5.7.3. The issue resides in the report PDF download/export functionality, where user-supplied values passed to the PDF generation pipeline or the wrapper invoking offline/pdf helper utilities are insufficiently validated or improperly escaped. This allows injection of shell metacharacters or arguments. The vulnerability has a CVSS v3.1 base score of 8.8 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).
An authenticated attacker with the ability to trigger PDF exports can exploit this vulnerability remotely over the network with low complexity and no user interaction required. Successful exploitation enables arbitrary command execution on the underlying system, potentially granting high-impact access to confidentiality, integrity, and availability.
Mitigation is addressed in the Nagios XI changelog at https://www.nagios.com/changelog/nagios-xi/, which details fixes in version 5.7.3 and later. Additional details on the vulnerability and remediation are available in the Vulncheck advisory at https://www.vulncheck.com/advisories/nagios-xi-command-injection-in-report-pdf-download.
Details
- CWE(s)