Werk #19868: Kubernetes: Fix crash when parsing Kubelet metric labels containing a null byte

Component

Checks & agents

Title

Kubernetes: Fix crash when parsing Kubelet metric labels containing a null byte

Date

Jun 15, 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
2.5.0p8 Not yet released	Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Cloud, Checkmk Ultimate MT

Previously, the Kubernetes special agent could crash when a Kubelet metric had a label value containing a null byte. Such values are valid in the Prometheus exposition format, but Checkmk failed to parse them.

The affected labels were found on metrics that Checkmk does not use anyway (only volume metrics are evaluated). Checkmk now skips parsing these unused metrics entirely, which avoids the crash.

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