subversion: multiple issues

• CVE-2016-2167 (authentication restriction bypass)

The canonicalize_username function in svnserve/cyrus_auth.c, when Cyrus
SASL authentication is used, allows remote attackers to authenticate
and bypass intended access restrictions via a realm string that is a
prefix of an expected repository realm string.

• CVE-2016-2168 (denial of service)

The req_check_access function in the mod_authz_svn module in the httpd
server allows remote authenticated users to cause a denial of service
(NULL pointer dereference and crash) via a crafted header in a (1) MOVE
or (2) COPY request, involving an authorization check.