Threat database

Nagios Core versions before 4.5.13 and Nagios XI versions before 2026R1.5 contain a Cross-Site Request Forgery (CSRF) vulnerability in the cmd.cgi component. This vulnerability allows attackers to bypass the double-submit cookie protection by supplying matching NagFormId and nagFormId values in the POST body when no Cookie header is present. Successful exploitation could enable execution of Nagios commands as an authenticated user. The CVSS 4.0 base score is 6.9, indicating a medium severity.

Nagios Core versions before 4.5.12 contain a cross-site request forgery (CSRF) vulnerability in the cmd.cgi component. The vulnerability arises because the CSRF protection mechanism incorrectly validates requests even when the NagFormId cookie is missing. This allows attackers to craft malicious cross-site POST requests that can execute arbitrary Nagios commands with the privileges of an authenticated user without their knowledge.

Nagios Core before 4.5.14 and Nagios XI before 2026R1.7 are vulnerable to authenticated remote code execution via unfiltered NOTIFICATION-family macro substitution through the com_data parameter. When a notification command references $NOTIFICATIONCOMMENT$ or $NOTIFICATIONAUTHOR$ in a shell-reachable position, authenticated UI users can run arbitrary commands as the nagios user. Exploitation requires a non-default configuration in which a notification command references these macros in a shell-executed command line.

Nagios Core before 4.5.13 and Nagios XI before 2026R1.5 are vulnerable to authenticated remote code execution via custom-variable macro injection through the Nagios Remote Data Processor (NRDP). When a custom variable defined on a host, service, or contact is referenced in a shell-executed command line, an authenticated attacker with NRDP access can inject OS commands through the macro value. Exploitation requires a non-default configuration in which a custom variable is defined and referenced in a shell-executed command.

Nagios Core before 4.5.14 and Nagios XI before 2026R1.7 are vulnerable to DOM-based cross-site scripting in jsonquery.js. Unencoded JSON string values reflected from stored fields are inserted into the DOM without sanitization, allowing attackers to run arbitrary JavaScript in the victim's browser.

Nagios Core before 4.5.14 and Nagios XI before 2026R1.7 contain a cross-site request forgery protection bypass via a self-supplied double-submit cookie. An attacker can supply matching cookie and request parameter values to bypass CSRF protection, enabling unauthenticated attackers to run commands as authorized users via malicious links.

Nagios Core before 4.5.14 and Nagios XI before 2026R1.7 are vulnerable to reflected cross-site scripting in cmd.cgi via the NagFormId parameter. An unauthenticated remote attacker can craft a malicious link that, when followed by an authenticated user, executes arbitrary JavaScript in the victim's browser.

Nagios XI versions prior to 2026R1.1 are vulnerable to local privilege escalation due to an unsafe interaction between sudo permissions and application file permissions. A user‑accessible maintenance script may be executed as root via sudo and includes an application file that is writable by a lower‑privileged user. A local attacker with access to the application account can modify this file to introduce malicious code, which is then executed with elevated privileges when the script is run. Successful exploitation results in arbitrary code execution as the root user.