dovecot -- multiple vulnerabilities

Dovecot team reports:

CVE-2021-29157: Dovecot does not correctly escape kid and azp
fields in JWT tokens.
This may be used to supply attacker controlled keys to validate
tokens in some configurations. This requires attacker
to be able to write files to
local disk.

CVE-2021-33515: On-path attacker could inject plaintext commands
before STARTTLS negotiation that would be executed after STARTTLS
finished with the client. Only the SMTP submission service is
affected.