Description
Nagios XI versions prior to 2024R1.2.2 contain a host header injection vulnerability. The application trusts the user-supplied HTTP Host header when constructing absolute URLs without sufficient validation. An unauthenticated, remote attacker can supply a crafted Host header to poison generated links or responses, which may facilitate phishing of credentials, account recovery link hijacking, and web cache poisoning.
Affected products
nagios: nagios xi
References3
- www.nagios.com/products/security/#nagios-xi Vendor Advisory
- www.nagios.com/changelog/nagios-xi/ Release Notes
- www.vulncheck.com/advisories/nagios-xi-host-header-injection Third Party Advisory
Metrics
- CVSS 3.1
-
6.1
MEDIUM
Score source: NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - CVSS 4.0
-
8.8
HIGH
Score source: CNA
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - EPSS — exploit probability
- 0% percentile: 41 · as of 10 November 2026
- CWE
- CWE-346
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.