The impersonate feature in Gitlab 8.7.0, 8.6.0 through 8.6.7, 8.5.0 through 8.5.11, 8.4.0 through 8.4.9, 8.3.0 through 8.3.8, and 8.2.0 through 8.2.4 allows remote authenticated users to "log in" as any other user via unspecified vectors.
https://gitlab.com/gitlab-org/gitlab-ce/issues/15548
https://about.gitlab.com/2016/05/02/cve-2016-4340-patches/
Source: Mitre, NVD
Published: 2017-01-23
Updated: 2017-01-25
Base Score: 6.5
Vector: CVSS2#AV:N/AC:L/Au:S/C:P/I:P/A:P
Severity: Medium
Base Score: 8.8
Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Severity: High