modules:
  - module: std
    versions:
      - fixed: 1.14.8
      - introduced: 1.15.0
        fixed: 1.15.1
    packages:
      - package: net/http/cgi
        symbols:
          - response.Write
          - response.WriteHeader
          - response.writeCGIHeader
      - package: net/http/fcgi
        symbols:
          - response.Write
          - response.WriteHeader
          - response.writeCGIHeader
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
credit: 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