CSRF in Nagios Enterprises, Llc. Core
CVE-2026-48549
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 class: CSRF (Cross-Site Request Forgery)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N.
EPSS exploit prediction
EPSS: 0.003 (15.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 16th percentile — 15.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001
Affected products
Weakness classification (CWE)
References
- www.nagios.com/security-disclosures/nagios-core/ (vendor-advisory, patch)
- github.com/NagiosEnterprises/nagioscore/blob/master/Changelog (release-notes)
- www.vulncheck.com/advisories/nagios-core-xi-csrf-via-cmd-cgi-double-submit-cook… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-48549?
- CVE-2026-48549 is a medium-severity vulnerability in Nagios Enterprises, Llc. Core, classified under Cross-Site Request Forgery (CSRF). CVSS score: 6.5/10. Published 2026-08-26.
- How severe is CVE-2026-48549?
- Medium severity. CVSS v3 base score is 6.5 out of 10.