CVE-2026-48549: Nagios Enterprises, Llc Nagios Core

Medium severity, CVSS 6.5. EPSS: 0.3% chance of exploitation in the next 30 days.

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.

Affected products

• Nagios Enterprises, Llc Nagios Core: before 4.5.13 (fixed in 4.5.13)
• Nagios Enterprises, Llc Nagios XI: before 2026R1.5 (fixed in 2026R1.5)

Published 2026-08-26. Last modified 2026-09-24.