There is a denial of service vulnerability in the header parsing component of Rack.
2.1.4-5ubuntu1.11.5.2-3+deb8u3ubuntu1~esm71.6.4-3ubuntu0.2+esm51.6.4-4ubuntu0.2+esm52.0.7-2ubuntu0.1+esm42.1.4-5ubuntu1+esm4Exploitability
AV:NAC:LPR:NUI:NScope
S:UImpact
C:LI:NA:NCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N