CVE-2026-48553: Nagios Enterprises, LLC. Nagios Core

Nagios Core / XI Authenticated RCE via Custom-Variable Macro Injection

CVSS 7.7 HighEPSS 0.0097 · 61st percentile

Published by the CVE Program (CNA: VulnCheck) at 12 Aug 2026, 16:46 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it.

Affected products, as the CNA wrote them
Vendor	Product	Versions
Nagios Enterprises, LLC.	Nagios Core	affected before 4.5.13 semver Other versions: affected
Nagios Enterprises, LLC.	Nagios XI	affected before 2026R1.5 custom Other versions: affected

Not analysed yet

We haven’t published our own analysis of this CVE. If a person reviews it, this page will say what’s affected and what has to be true for it to matter.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
7.7	High	4.0	CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N	CNA (VulnCheck)Used for this record
7.5	High	3.1	CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H	CNA (VulnCheck)

CISA KEV Not listed.
EPSS 0.0097, the 61st percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

This record came from the full history of the CVE Program, published 12 Aug 2026. New records show when each source confirmed them.

Sources

References from the CNA

www.nagios.com/security-disclosures/nagios-core/ vendor-advisorypatch
github.com/NagiosEnterprises/nagioscore/blob/master/Changelog release-notes
www.vulncheck.com/advisories/nagios-core-xi-authenticated-rce-via-custom-variable-macro-injection third-party-advisory

Facts on this page come from the CVE List as the CNA published them, with CVSS from the sources named above, CISA KEV and FIRST EPSS. Vendors, products and versions are shown as the CNA wrote them. We don’t reproduce the CVE’s description.