ssh_pki_export_privkey_base64() fails

When using the default SSH host RSA key generated by OpenSSH, it fails to export after being imported. I have tried to debug this but ended up with a bogus memory allocation fail error in OpenSSL so I am not sure whether the problem is in libssh or OpenSSL. Can be reproduced with the attached example. I am using libssh v0.10.6 and OpenSSL v3.1.14.

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