A flaw was found in Keystone. There is a time lag (up to one hour in a default configuration) between when security policy says a token should be revoked from when it is actually revoked. This could allow a remote administrator to secretly maintain access for longer than expected.
Exploitability
AV:NAC:HPR:HUI:NScope
S:UImpact
C:HI:HA:H6.6/CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:HOther