In pkg/tool/path.go in Gogs before 0.11.82.1218, a directory traversal in the file-upload functionality can allow an attacker to create a file under data/sessions on the server, a similar issue to CVE-2018-18925.
Gogs 0.11.66 allows remote code execution because it does not properly validate session IDs, as demonstrated by a ".." session-file forgery in the file session provider in file.go. This is related to session ID handling in the go-macaron/session code for Macaron.
In Gogs 0.11.53, an attacker can use a crafted .eml file to trigger MIME type sniffing, which leads to XSS, as demonstrated by Internet Explorer, because an "X-Content-Type-Options: nosniff" header is not sent.
Open redirect vulnerability in Gogs before 0.12 allows remote attackers to redirect users to arbitrary websites and conduct phishing attacks via an initial /\ substring in the user/login redirect_to parameter, related to the function isValidRedirect in routes/user/auth.go.