An issue was discovered in Zammad before 3.4.1. There are wrong authorization checks for impersonation requests via X-On-Behalf-Of. The authorization checks are performed for the actual user and not the one given in the X-On-Behalf-Of header.
Source: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-26029
Reference (s):
- https://zammad.com/news/security-advisory-zaa-2020-20