CVE-2026-59647: CRMF/CMP password-MAC honours unbounded iteration count

Affects Bouncy Castle for Java before 1.85. PKMACBuilder’s default constructor leaves the iteration ceiling disabled, so when a CA or RA verifies a password-MAC protected CMP or CRMF message the iteration count is taken from the attacker’s PBMParameter and drives the digest loop unbounded. A count near 2^31 occupies a server thread for hours, and a small number of requests exhausts the thread pool. The same unbounded pattern applies to CMS PasswordRecipientInfo handling.