The problem can be corrected by upgrading the affected package to
version 2.0.50-12ubuntu4.2 (for Ubuntu 4.10) and 2.0.53-5ubuntu5.1
(for Ubuntu 5.04). In general, a standard system upgrade is
sufficient to effect the necessary changes.
Luca Ercoli discovered that the "htdigest" program did not perform any
bounds checking when it copied the "user" and "realm" arguments into
local buffers. If this program is used in remotely callable CGI
scripts, this could be exploited by a remote attacker to execute
arbitrary code with the privileges of the CGI script.