In VOS user session identifier (authentication token) is issued to the browser prior to authentication but is not changed after the user successfully logs into the application. Failing to issue a new session ID following a successful login introduces the possibility for an attacker to set up a trap session on the device the victim is likely to login with.

References

• https://nvd.nist.gov/vuln/detail/CVE-2018-16495
• https://hackerone.com/reports/1168192