Nagios Core <=4.5.13 CVE-2026-48549: CSRF via cmd.cgi cookie bypass
CVE-2026-48549 Published on August 26, 2026
Nagios Core / XI CSRF via cmd.cgi Double-Submit Cookie
Nagios Core before 4.5.13 and Nagios XI before 2026R1.5 contains a CSRF vulnerability in cmd.cgi. When no Cookie header is present, the double-submit cookie protection can be bypassed by supplying matching NagFormId and nagFormId values in the POST body, allowing a cross-site request to execute Nagios commands as a currently authenticated user.
Vulnerability Analysis
CVE-2026-48549 can be exploited with network access. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity and availability.
Weakness Type
What is a Session Riding Vulnerability?
The web application does not, or can not, sufficiently verify whether a well-formed, valid, consistent request was intentionally provided by the user who submitted the request. When a web server is designed to receive a request from a client without any mechanism for verifying that it was intentionally sent, then it might be possible for an attacker to trick a client into making an unintentional request to the web server which will be treated as an authentic request. This can be done via a URL, image load, XMLHttpRequest, etc. and can result in exposure of data or unintended code execution.
CVE-2026-48549 has been classified to as a Session Riding vulnerability or weakness.
Products Associated with CVE-2026-48549
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Affected Versions
Nagios Enterprises, LLC. Nagios Core:- Before 4.5.13 is affected.
- Before 2026R1.5 is affected.