CVE-2026-61551Network attack vectorHinoki check available

Service crash via unbounded recursive JSON parsing

Published Sep 18, 2026 · Updated Sep 18, 2026

Uncontrolled recursion in Icinga 2 before 2.14.9, 2.15.0 through 2.15.3, or 2.16.0 through 2.16.1 allows remote attackers to crash the service. The JSON decoder recursively traverses arrays and objects without a nesting-depth limit, exhausting the coroutine call stack on deeply nested input. Unauthenticated network access to TCP port 5665 is sufficient; code execution remains unproven, so the demonstrated consequence is a process crash.

CVSS severity8.6
High
EPSS probability0.94%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Get started

Summary

What happened

Uncontrolled recursion in Icinga 2 before 2.14.9, 2.15.0 through 2.15.3, or 2.16.0 through 2.16.1 allows remote attackers to crash the service. The JSON decoder recursively traverses arrays and objects without a nesting-depth limit, exhausting the coroutine call stack on deeply nested input. Unauthenticated network access to TCP port 5665 is sufficient; code execution remains unproven, so the demonstrated consequence is a process crash.

The record

CVE
CVE-2026-61551
Published
Sep 18, 2026
Updated
Sep 18, 2026
Vendor
Icinga
Product
Icinga 2
Classifications
CWE-674, T1499.004
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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=< 2.14.9
  2. Affected versionversion=>= 2.15.0, < 2.15.4
  3. Affected versionversion=>= 2.16.0, < 2.16.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

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

Published CVSS scores

8.6GitHub CNACVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/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-674Uncontrolled Recursion
T1499.004Application or System Exploitation

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

See the directory against your own environment.

Your stack

Check the software in your environment

Get started to see how Hinoki identifies affected software and validates exploitability in your environment.

Get started