LibYAML input sanitization errors

oCERT reports:

The LibYAML project is an open source YAML 1.1 parser and
emitter written in C.
The library is affected by a heap-based buffer overflow
which can lead to arbitrary code execution. The
vulnerability is caused by lack of proper expansion for the
string passed to the yaml_parser_scan_uri_escapes()
function.
A specially crafted YAML file, with a long sequence of
percent-encoded characters in a URL, can be used to trigger
the overflow.