CVE-2019-16782: Fedoraproject Fedora

Medium severity, CVSS 5.9. EPSS: 3.7% chance of exploitation in the next 30 days.

There's a possible information leak / session hijack vulnerability in Rack (RubyGem rack). This vulnerability is patched in versions 1.6.12 and 2.0.8. Attackers may be able to find and hijack sessions by using timing attacks targeting the session id. Session ids are usually stored and indexed in a database that uses some kind of scheme for speeding up lookups of that session id. By carefully measuring the amount of time it takes to look up a session, an attacker may be able to find a valid session id and hijack the session. The session id itself may be generated randomly, but the way the session is indexed by the backing store does not use a secure comparison.

Affected products

• Fedoraproject Fedora: version 31 only
• Opensuse Leap: version 15.1 only
• Rack Rack: before 1.6.12 (fixed in 1.6.12); from 2.0.0, before 2.0.8 (fixed in 2.0.8)

Published 2019-12-18. Last modified 2026-06-17.