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.
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CVSS_V3