CVE-2026-48551 Nagios Core / XI CSRF Protection Bypass via Double-Submit Cookie
Attackers can bypass CSRF protection to execute commands as authorized users via malicious links in Nagios Core and XI.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-48551?
CVE-2026-48551 is a medium-severity vulnerability in Nagios Core, published on 12 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
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.
Weakness: CWE-352
Which versions are affected by CVE-2026-48551?
How do I fix CVE-2026-48551?
Upgrade to a fixed version.
Is CVE-2026-48551 being exploited?
There is no known exploitation of CVE-2026-48551 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-48551, GHSA-4f3c-j3m4-8h7h, UBUNTU-CVE-2026-48551.