Jinja is a template engine written in pure Python.
The ‘urlize’ filter in Jinja utilized an inefficient regular expression that could be exploited to consume excess CPU.
An attacker could cause a Denial of Service condition via crafted input to the ‘urlize’ Jinja filter.
There is no known workaround at this time.
All Jinja users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=dev-python/jinja-2.11.3"