What’s Vulnerable › Vulnerabilities

CVE-2026-48554: Nagios Core / XI Authenticated RCE via Unfiltered NOTIFICATION-Family Macro Substitution

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.0% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-12 · updated 2026-09-08
• Weakness: CWE-78

Description

Nagios Core before 4.5.14 and Nagios XI before 2026R1.7 are vulnerable to authenticated remote code execution via unfiltered NOTIFICATION-family macro substitution through the com_data parameter. When a notification command references $NOTIFICATIONCOMMENT$ or $NOTIFICATIONAUTHOR$ in a shell-reachable position, authenticated UI users can run arbitrary commands as the nagios user. Exploitation requires a non-default configuration in which a notification command references these macros in a shell-executed command line.

Affected products

• Nagios Enterprises, LLC. Nagios Core: before 4.5.14 — fixed in 4.5.14
• Nagios Enterprises, LLC. Nagios XI: before 2026R1.7 — fixed in 2026R1.7

How to fix

Upgrade to a fixed version: Nagios Enterprises, LLC. Nagios Core 4.5.14; Nagios Enterprises, LLC. Nagios XI 2026R1.7. Check the vendor advisory for mitigations.

References

• https://github.com/NagiosEnterprises/nagioscore/blob/master/Changelog
• https://www.nagios.com/security-disclosures/nagios-core/
• https://www.vulncheck.com/advisories/nagios-core-xi-authenticated-rce-via-unfiltered-notification-family-macro-substitution

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