CVE-2026-61550Network attack vectorHinoki check available

Node takeover via unauthenticated certificate replacement

Published Sep 18, 2026 · Updated Sep 18, 2026

Improper access control in Icinga 2 allows remote attackers to replace its node and trusted CA certificates through TCP port 5665. UpdateCertificateHandler accepted certificate-update messages from clients without first requiring a mapped endpoint object. Network reachability alone is sufficient; the substituted CA permits trusted-node impersonation and control of the affected node.

CVSS severity9.8
Critical
EPSS probability0.67%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
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Summary

What happened

Improper access control in Icinga 2 allows remote attackers to replace its node and trusted CA certificates through TCP port 5665. UpdateCertificateHandler accepted certificate-update messages from clients without first requiring a mapped endpoint object. Network reachability alone is sufficient; the substituted CA permits trusted-node impersonation and control of the affected node.

The record

CVE
CVE-2026-61550
Published
Sep 18, 2026
Updated
Sep 18, 2026
Vendor
Icinga
Product
Icinga 2
Classifications
CWE-862, T1553.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 18, 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=>= 2.15.0, < 2.15.4
  2. Affected versionversion=>= 2.16.0, < 2.16.2
  3. Affected versionversion=>= 2.8, < 2.14.9

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Icinga · Icinga 2version=>= 2.15.0, < 2.15.4; version=>= 2.16.0, < 2.16.2; version=>= 2.8, < 2.14.9

Published CVSS scores

9.8GitHub Security AdvisoryCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-862Missing Authorization
T1553.004Subvert Trust Controls: Install Root Certificate

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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