Jenkins 2.299 and earlier, LTS 2.289.1 and earlier does not invalidate the previous session on login.
https://www.jenkins.io/security/advisory/2021-06-30/#SECURITY-2371
Source: MITRE
Published: 2021-06-30
Updated: 2021-07-06
Type: CWE-384
Base Score: 5.1
Vector: AV:N/AC:H/Au:N/C:P/I:P/A:P
Impact Score: 6.4
Exploitability Score: 4.9
Severity: MEDIUM
Base Score: 7.5
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
Impact Score: 5.9
Exploitability Score: 1.6
Severity: HIGH