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Werk #18706: Fix host_label parsing to handle ":" in label value

Component User interface
Title Fix host_label parsing to handle ":" in label value
Date Jan 29, 2026
Level Trivial Change
Class Bug Fix
Compatibility Compatible - no manual interaction needed
Checkmk versions & editions
2.6.0b1
Not yet released
Checkmk Raw (CRE), Checkmk Enterprise (CEE), Checkmk Cloud (CCE), Checkmk MSP (CME)
2.5.0b1
Not yet released
Checkmk Raw (CRE), Checkmk Enterprise (CEE), Checkmk Cloud (CCE), Checkmk MSP (CME)
2.4.0p22
Not yet released
Checkmk Raw (CRE), Checkmk Enterprise (CEE), Checkmk Cloud (CCE), Checkmk MSP (CME)

Host labels were previously split at each colon, which caused parts of the host label value to be lost if it contained a colon.

For example, the label cmk/label_key:label_value:with:colon was parsed as key = label_key and value = label_value, truncating the remainder.

Now, the entire value after the first colon is preserved, so the value is correctly recognized as label_value:with:colon.

Users who use host labels containing colons in rule definitions are affected by this change. After upgrading, please review and, if necessary, update your rule definitions to ensure they still match the new label parsing behavior. Reload or update your rules using the appropriate Checkmk commands to apply these changes and maintain correct monitoring.

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