CVE-2026-48553Network attack vectorHinoki check available

Authenticated code execution via custom-variable macro injection

Published Aug 12, 2026 · Updated Aug 12, 2026

OS command injection in Nagios Core before 4.5.13 and Nagios XI before 2026R1.5 allows remote authenticated users to execute commands via NRDP. NRDP-supplied host, service, or contact custom-variable values reach shell-executed command lines without adequate metacharacter neutralization. Exploitation requires NRDP access and a non-default command definition that references the attacker-controlled custom variable; commands run as the Nagios process user.

CVSS severity7.7
High
EPSS probability0.52%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

OS command injection in Nagios Core before 4.5.13 and Nagios XI before 2026R1.5 allows remote authenticated users to execute commands via NRDP. NRDP-supplied host, service, or contact custom-variable values reach shell-executed command lines without adequate metacharacter neutralization. Exploitation requires NRDP access and a non-default command definition that references the attacker-controlled custom variable; commands run as the Nagios process user.

The record

CVE
CVE-2026-48553
Published
Aug 12, 2026
Updated
Aug 12, 2026
Vendor
Nagios Enterprises, LLC
Product
Nagios Core
Classifications
CWE-78, T1059
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 12, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 12, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <4.5.13

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Nagios Enterprises, LLC · Nagios Coreversion=0 <4.5.13
Nagios Enterprises, LLC · Nagios XIversion=0 <2026R1.5

Published CVSS scores

7.5UbuntuCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
7.7VulnCheckCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
T1059Command and Scripting Interpreter

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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