CVE-2026-48551: Nagios Enterprises, Llc Nagios Core

High severity, CVSS 7.4. EPSS: 0.3% chance of exploitation in the next 30 days.

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.

Affected products

• Nagios Enterprises, Llc Nagios Core: before 4.5.14 (fixed in 4.5.14)
• Nagios Enterprises, Llc Nagios XI: before 2026R1.7 (fixed in 2026R1.7)

Published 2026-08-12. Last modified 2026-09-08.