Auth bypass in Icinga Icinga2

CVE-2026-61550

Icinga 2 is an open source monitoring system. From 2.8 until 2.14.9, 2.15.4, and 2.16.2, certificate update JSON-RPC message handling does not validate that the sender is a trusted endpoint. An unauthenticated network attacker able to connect to TCP port 5665 can replace the node certificate and trusted CA certificate, impersonate a trusted node, and take control of the node. This issue is fixed in versions 2.14.9, 2.15.4, and 2.16.2.

Vulnerability class: Broken Access Control

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.007 (52.2th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 52nd percentile — 52.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-61550: held from 0.007 to 0.007.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000

Affected products

  • Icinga Icinga2 — versions >= 2.15.0, < 2.15.4, >= 2.16.0, < 2.16.2, >= 2.8, < 2.14.9

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-61550?
CVE-2026-61550 is a critical-severity vulnerability in Icinga Icinga2, classified under Missing Authorization. CVSS score: 9.8/10. Published 2026-09-18.
How severe is CVE-2026-61550?
Critical severity. CVSS v3 base score is 9.8 out of 10.