A potential HTTP request smuggling vulnerability in WEBrick was reported.

WEBrick (bundled along with jruby) 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 9 stretch, this problem has been fixed in version 1.7.26-1+deb9u3.

We recommend that you upgrade your jruby packages.

For the detailed security status of jruby please refer to its security tracker page at: https://security-tracker.debian.org/tracker/jruby

Further information about Debian LTS security advisories, how to apply these updates to your system and frequently asked questions can be found at: https://wiki.debian.org/LTS