Jenkins 2.274 and earlier, LTS 2.263.1 and earlier allows reading arbitrary files using the file browser for workspaces and archived artifacts by following symlinks.
https://www.jenkins.io/security/advisory/2021-01-13/#SECURITY-1452
Source: MITRE
Published: 2021-01-13
Updated: 2021-01-15
Type: CWE-59
Base Score: 4
Vector: AV:N/AC:L/Au:S/C:P/I:N/A:N
Impact Score: 2.9
Exploitability Score: 8
Severity: MEDIUM
Base Score: 6.5
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Impact Score: 3.6
Exploitability Score: 2.8
Severity: MEDIUM