Werk #19905: Fix crash on hosts with null values in meta_data

Component

REST API

Title

Fix crash on hosts with null values in meta_data

Date

Jul 21, 2026

Level

Trivial Change

Class

Bug Fix

Compatibility

Compatible - no manual interaction needed

Checkmk versions & editions

3.0.0b1 Not yet released	Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Cloud, Checkmk Ultimate MT
2.5.0p10 Not yet released	Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Cloud, Checkmk Ultimate MT

The REST API crashed when serializing the attributes of a host or folder whose meta_data attribute contained explicit null values for created_at, updated_at or created_by instead of omitting the keys entirely.

This also affected the Dynamic host configuration (DCD), which uses these endpoints and crashed when processing such hosts.

The REST API now treats null values in meta_data the same as missing keys and omits the corresponding fields from the response.

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