CVE-2026-61551

Icinga 2: Stack overflow via deeply nested JSON objects

8.6 HighFix available

Icinga 2 is an open source monitoring system. Prior to 2.14.9, 2.15.4, and 2.16.2, parsing deeply nested JSON can exhaust the call stack because nesting depth is not bounded. The affected JSON parsing paths are reachable by unauthenticated network clients through the Icinga 2 service on TCP port 5665, allowing a remote attacker to crash the process, while possible code execution has not been demonstrated. This issue is fixed in versions 2.14.9, 2.15.4, and 2.16.2.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: Low
Integrity: Low
Availability: High

Exploit likelihood

0.94%Up 0.4 points since Sep 19, 2026

What each source reports

CVE List Score used 8.6

Icinga 2: Stack overflow via deeply nested JSON objects

Record: CVE-2026-61551
CVSS 3.1: 8.6 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
Weakness: CWE-674
Updated: 2026-11-02

EUVDEUVD-2026-83209 8.6

Record: EUVD-2026-83209
CVSS 3.1: 8.6 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
Updated: 2026-11-02

NVD 8.6

Record: CVE-2026-61551
CVSS 3.1: 8.6 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
Weakness: CWE-674
Updated: 2026-11-02

OSV 8.6

Icinga 2: Stack overflow via deeply nested JSON objects

Record: CVE-2026-61551
CVSS 3.1: 8.6 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
Weakness: CWE-674
Updated: 2026-11-02

OSVDEBIAN-CVE-2026-61551 8.6

Record: DEBIAN-CVE-2026-61551
CVSS 3.1: 8.6 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
Updated: 2026-11-02

OSVUBUNTU-CVE-2026-61551 8.6

Record: UBUNTU-CVE-2026-61551
CVSS 3.1: 8.6 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
Updated: 2026-11-04

Affected products

icinga icinga2

Affected packages

Affected packages
Package	Affected	Fixed
`icinga2` Debian:12	All versions, plus listed versions 2.13.6-22.13.6-2+deb12u12.13.6-2+deb12u22.13.7-12.13.7-1~exp1 Show 27 moreShow less 2.13.8-12.14.0-1~exp12.14.1-12.14.2-12.14.2-1+loong642.14.3-12.14.4-12.14.5-12.14.6-12.15.0-12.15.0-1~exp12.15.1-12.15.2-12.15.2-22.16.0-12.16.0-22.16.0-3~exp12.16.0-3~exp22.16.0-3~exp32.16.0-3~exp42.16.1-12.16.1-1~exp12.16.2-12.16.2-22.16.3-12.16.4-12.16.5-1	None known
`icinga2` Debian:13	before 2.14.6-1+deb13u1, plus listed versions 2.14.6-1	2.14.6-1+deb13u1
`icinga2` Debian:14	before 2.16.2-1, plus listed versions 2.14.6-12.15.0-12.15.0-1~exp12.15.1-12.15.2-1 Show 9 moreShow less 2.15.2-22.16.0-12.16.0-22.16.0-3~exp12.16.0-3~exp22.16.0-3~exp32.16.0-3~exp42.16.1-12.16.1-1~exp1	2.16.2-1
`icinga2` Ubuntu:18.04:LTS	All versions, plus listed versions 2.7.0-12.8.1-0ubuntu2	None known
`icinga2` Ubuntu:20.04:LTS	All versions, plus listed versions 2.10.5-1build12.11.2-12.11.2-1ubuntu12.11.2-1ubuntu22.11.2-1ubuntu3	None known
`icinga2` Ubuntu:22.04:LTS	All versions, plus listed versions 2.12.3-12.13.1-12.13.2-12.13.2-1build12.13.2-1build2	None known
`icinga2` Ubuntu:24.04:LTS	All versions, plus listed versions 2.13.8-12.14.1-12.14.2-12.14.2-1build12.14.2-1build2	None known
`icinga2` Ubuntu:26.04:LTS	All versions, plus listed versions 2.15.0-12.15.1-1	None known

History

History
Recorded	Changed	Sources
Nov 4, 2026	affected, facts	OSV
Nov 2, 2026	first indexed	CVE List, EUVD, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-61551 is a high vulnerability (CVSS 8.6) in Icinga Icinga2, published September 18, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.94%, the 61st percentile. Fixed in icinga2 2.14.6-1+deb13u1.

References

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