CVE-2026-48549

Nagios Core / XI CSRF via cmd.cgi Double-Submit Cookie

6.9 MediumFix available

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.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: Active

What an attacker can affect

Confidentiality: None
Integrity: High
Availability: None

Exploit likelihood

0.26%Up 0.1 points since Aug 27, 2026

What each source reports

CVE List Score used 6.9

Nagios Core / XI CSRF via cmd.cgi Double-Submit Cookie

Record: CVE-2026-48549
CVSS 4.0: 6.9 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
Weakness: CWE-352
Updated: 2026-11-02

EUVDEUVD-2026-66599 6.9

Record: EUVD-2026-66599
CVSS 4.0: 6.9 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
Updated: 2026-11-02

GitHub AdvisoriesGHSA-xm5q-p2r5-r5wj 6.9

Nagios Core before 4.5.13 and Nagios XI before 2026R1.5 contains a CSRF vulnerability in cmd.cgi....

Record: GHSA-xm5q-p2r5-r5wj
CVSS 4.0: 6.9 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/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
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
Weakness: CWE-352
Updated: 2026-11-02

NVD 6.9

Record: CVE-2026-48549
CVSS 4.0: 6.9 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/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
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
Weakness: CWE-352
Updated: 2026-11-02

OSV 6.9

Nagios Core / XI CSRF via cmd.cgi Double-Submit Cookie

Record: CVE-2026-48549
CVSS 4.0: 6.9 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
Weakness: CWE-352
Updated: 2026-11-02

OSVDEBIAN-CVE-2026-48549 6.9

Record: DEBIAN-CVE-2026-48549
CVSS 4.0: 6.9 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/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
Updated: 2026-11-02

OSVUBUNTU-CVE-2026-48549 6.9

Record: UBUNTU-CVE-2026-48549
CVSS 4.0: 6.9 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
Updated: 2026-11-02

Affected products

Affected packages

Affected packages
Package	Affected	Fixed
`nagios4` Debian:12	before 4.4.6-4+deb12u2, plus listed versions 4.4.6-44.4.6-4+deb12u1	4.4.6-4+deb12u2
`nagios4` Debian:13	before 4.4.6-4.1+deb13u2, plus listed versions 4.4.6-4.14.4.6-4.1+deb13u1	4.4.6-4.1+deb13u2
`nagios4` Debian:14	before 4.5.14+ds-1, plus listed versions 4.4.6-4.14.5.12+ds-1	4.5.14+ds-1
`nagios4` Ubuntu:20.04:LTS	All versions, plus listed versions 4.3.4-34.3.4-3ubuntu0.1	None known
`nagios4` Ubuntu:22.04:LTS	All versions, plus listed versions 4.4.6-44.4.6-4ubuntu0.22.04.1	None known
`nagios4` Ubuntu:24.04:LTS	All versions, plus listed versions 4.4.6-44.4.6-4ubuntu0.24.04.1	None known
`nagios4` Ubuntu:26.10	All versions, plus listed versions 4.4.6-4.1ubuntu2	None known
`nagios4` Ubuntu:26.04:LTS	All versions, plus listed versions 4.4.6-4.1ubuntu14.4.6-4.1ubuntu2	None known

History

History
Recorded	Changed	Sources
Nov 2, 2026	first indexed	CVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-48549 is a medium vulnerability (CVSS 6.9) in Nagios Enterprises Xi, published August 26, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.26%, the 17th percentile. Fixed in nagios4 4.4.6-4+deb12u2.