CVE-2026-48553

High

Description

Nagios Core before 4.5.13 and Nagios XI before 2026R1.5 are vulnerable to authenticated remote code execution via custom-variable macro injection through the Nagios Remote Data Processor (NRDP). When a custom variable defined on a host, service, or contact is referenced in a shell-executed command line, an authenticated attacker with NRDP access can inject OS commands through the macro value. Exploitation requires a non-default configuration in which a custom variable is defined and referenced in a shell-executed command.

SeverityHigh

CVSS7.5

Exploit probability—

ProductNagios Core

PublishedAug 12, 2026

First seenAug 12, 2026

Weakness typeCWE-78OS command injection

How to fix

Update

Nagios Enterprises, LLC. Nagios Core4.5.13 or later
Nagios Enterprises, LLC. Nagios XI2026R1.5 or later

Patches

nagios.com/security-disclosures/nagios-core/

Vendor advisories

github.com/NagiosEnterprises/nagioscore/blob/master/Changelog

Affected products

Product	Affected versions	Fixed in
Nagios Enterprises, LLC. Nagios Core	v < 4.5.13	4.5.13
Nagios Enterprises, LLC. Nagios XI	v < 2026R1.5	2026R1.5

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