A potential HTTP request smuggling vulnerability in WEBrick was reported.
WEBrick (bundled along with ruby2.1) was too tolerant against an invalid Transfer-Encoding header. This may lead to inconsistent interpretation between WEBrick and some HTTP proxy servers, which may allow the attacker to “smuggle” a request.
For Debian 8 jessie, these problems have been fixed in version 2.1.5-2+deb8u11.
We recommend that you upgrade your ruby2.1 packages.
Further information about Extended LTS security advisories can be found at: https://deb.freexian.com/extended-lts/