Vulnerability · Published Aug 26, 2026 · Assigned by VulnCheck
CVE-2026-48549Nagios Core / XI CSRF via cmd.cgi Double-Submit Cookie
Medium 6.5
In plain English
A medium-severity cross-site request forgery in Nagios Core from Nagios Enterprises, LLC.. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 17% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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 packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | nagios4 | 4.4.6-4+deb12u2 | DEBIAN-CVE-2026-48549 |
| Debian:13 | nagios4 | 4.4.6-4.1+deb13u2 | DEBIAN-CVE-2026-48549 |
| Debian:14 | nagios4 | 4.5.14+ds-1 | DEBIAN-CVE-2026-48549 |
| Ubuntu:22.04:LTS | nagios4 | no fix listed | UBUNTU-CVE-2026-48549 |
| Ubuntu:24.04:LTS | nagios4 | no fix listed | UBUNTU-CVE-2026-48549 |
| Ubuntu:26.04:LTS | nagios4 | no fix listed | UBUNTU-CVE-2026-48549 |
| Ubuntu:26.10 | nagios4 | no fix listed | UBUNTU-CVE-2026-48549 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Nagios Enterprises, LLC. | Nagios Core | 0 – before 4.5.13 |
| Nagios Enterprises, LLC. | Nagios XI | 0 – before 2026R1.5 |
Weakness: CWE-352 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
References
- Security Disclosures vendor-advisory, patch
- Changelog release-notes
- https://www.vulncheck.com/advisories/nagios-core-xi-csrf-via-cmd-cgi-double-submit-cookie third-party-advisory