Werk #22348: winperf_if: do not crash on error lines in the network adapter data

Component	Checks & agents
Title	winperf_if: do not crash on error lines in the network adapter data
Date	Sep 22, 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 2.5.0p15 Not yet released Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Cloud, Checkmk Ultimate MT 2.4.0p38 Not yet released Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Cloud, Checkmk Ultimate MT

When the script host on a monitored Windows host failed while collecting network adapter details, the agent appended its own error message to the section, for example CScript Error: Execution of the Windows Script Host failed. (0x8007000E).

Checkmk could not read that line and gave up on the whole section with IndexError: list index out of range. A crash report was created on every check cycle, and every interface of the affected host lost its alias, speed, MAC address and connection status, because none of the adapter details could be read any more.

Lines that do not carry a complete set of adapter details are now ignored. The adapters the agent did report are monitored with their details as before.

Checkmk does not surface the agent's own error message; it only no longer lets that message stop the remaining adapters from being monitored.

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