An issue was discovered in the Security component in Symfony 2.7.x before 2.7.48, 2.8.x before 2.8.41, 3.3.x before 3.3.17, 3.4.x before 3.4.11, and 4.0.x before 4.0.11. By default, a user’s session is invalidated when the user is logged out. This behavior can be disabled through the invalidate_session option. In this case, CSRF tokens were not erased during logout which allowed for CSRF token fixation.
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/G4XNBMFW33H47O5TZGA7JYCVLDBCXAJV/
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UBQK7JDXIELADIPGZIOUCZKMAJM5LSBW/
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WU5N2TZFNGXDGMXMPP7LZCWTFLENF6WH/
symfony.com/blog/cve-2018-11406-csrf-token-fixation
www.debian.org/security/2018/dsa-4262