subversion -- Unrestricted XML entity expansion in mod_dontdothat and Subversionclients using http(s)

The Apache Software Foundation reports:

The mod_dontdothat module of subversion and subversion clients using
http(s):// are vulnerable to a denial-of-service attack, caused by
exponential XML entity expansion. The attack targets XML parsers
causing targeted process to consume excessive amounts of resources.
The attack is also known as the “billions of laughs attack.”