Privoxy -- Multiple vulnerabilities (memory leak, XSS)

Privoxy reports:

cgi_error_no_template(): Encode the template name to prevent
XSS (cross-site scripting) when Privoxy is configured to servce
the user-manual itself.
Commit 0e668e9409c. OVE-20211102-0001. CVE-2021-44543.
Reported by: Artem Ivanov
get_url_spec_param(): Free memory of compiled pattern spec
before bailing.
Reported by Joshua Rogers (Opera) who also provided the fix.
Commit 652b4b7cb0. OVE-20211201-0003. CVE-2021-44540.
process_encrypted_request_headers(): Free header memory when
failing to get the request destination.
Reported by Joshua Rogers (Opera) who also provided the fix.
Commit 0509c58045. OVE-20211201-0002. CVE-2021-44541.
send_http_request(): Prevent memory leaks when handling errors
Reported by Joshua Rogers (Opera) who also provided the fix.
Commit c48d1d6d08. OVE-20211201-0001. CVE-2021-44542.