If an X.509 certificate contains a malformed policy constraint and
policy processing is enabled, then a write lock will be taken twice
recursively. On some operating systems (most widely: Windows) this
results in a denial of service when the affected process hangs. Policy
processing being enabled on a publicly facing server is not considered
to be a common setup.
Policy processing is enabled by passing the `-policy\'
argument to the command line utilities or by calling the
`X509_VERIFY_PARAM_set1_policies()\' function.
Update (31 March 2023): The description of the policy processing enablement
was corrected based on CVE-2023-0466.