Werk #19901: vsphere: fix login failure when password contains non-ASCII characters

Component	Checks & agents
Title	vsphere: fix login failure when password contains non-ASCII characters
Date	Apr 29, 2026
Level	Trivial Change
Class	Bug Fix
Compatibility	Compatible - no manual interaction needed
Checkmk versions & editions	2.6.0b1 Not yet released Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Cloud, Checkmk Ultimate MT 2.5.0p2 Not yet released Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Cloud, Checkmk Ultimate MT 2.4.0p29 Not yet released Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Cloud, Checkmk Ultimate MT 2.3.0p47 Not yet released Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Ultimate MT

The vSphere special agent failed to authenticate against vCenter when the configured password contained non-ASCII characters such as §. vCenter rejected the request with HTTP 500 and the agent reported:

Cannot login to vSphere Server (...). Please check the credentials.

even though the same credentials worked in the vCenter Web UI.

The SOAP envelope was sent as a Python str, which the requests library encodes as latin-1, while the request's Content-Type header declared charset="utf-8". vCenter parsed the body as UTF-8 and rejected the mismatched bytes.

The agent now encodes the SOAP body as UTF-8 to match the declared charset, so non-ASCII characters in passwords (and usernames) round-trip correctly.

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