id: GO-2021-0226
modules:
    - module: std
      versions:
        - fixed: 1.14.8
        - introduced: 1.15.0-0
          fixed: 1.15.1
      vulnerable_at: 1.15.0
      packages:
        - package: net/http/cgi
          symbols:
            - response.Write
            - response.WriteHeader
            - response.writeCGIHeader
          skip_fix: 'TODO: revisit this reason (fix appears to not work with Go <1.18)'
        - package: net/http/fcgi
          symbols:
            - response.Write
            - response.WriteHeader
            - response.writeCGIHeader
          skip_fix: 'TODO: revisit this reason (fix appears to not work with Go <1.18)'
summary: Cross-site scripting in net/http/cgi and net/http/fcgi
description: |-
    When a Handler does not explicitly set the Content-Type header, the the package
    would default to “text/html”, which could cause a Cross-Site Scripting
    vulnerability if an attacker can control any part of the contents of a response.

    The Content-Type header is now set based on the contents of the first Write
    using http.DetectContentType, which is consistent with the behavior of the
    net/http package.

    Although this protects some applications that validate the contents of uploaded
    files, not setting the Content-Type header explicitly on any attacker-controlled
    file is unsafe and should be avoided.
published: 2022-01-13T03:44:58Z
cves:
    - CVE-2020-24553
credits:
    - RedTeam Pentesting GmbH
references:
    - fix: https://go.dev/cl/252179
    - fix: https://go.googlesource.com/go/+/4f5cd0c0331943c7ec72df3b827d972584f77833
    - web: https://groups.google.com/g/golang-announce/c/8wqlSbkLdPs
    - report: https://go.dev/issue/40928