knot-resolver before version 4.3.0 is vulnerable to denial of service through high CPU utilization. DNS replies with very many resource records might be processed very inefficiently, in extreme cases taking even several CPU seconds for each such uncached message. For example, a few thousand A records can be squashed into one DNS message (limit is 64kB).

perl-Email-Address: Specially crafted input could cause Denial of Service due to complex parse() method

The parse() method in the Email::Address module through 1.909 for Perl is vulnerable to Algorithmic complexity on specially prepared input, leading to Denial of Service. Prepared special input that caused this problem contained 30 form-field characters ("\f").

PyXML: hash table collisions CPU usage DoS (oCERT-2011-003)

PyXML: Hash table collisions CPU usage Denial of Service