net/url in Go before 1.11.13 and 1.12.x before 1.12.8 mishandles malformed hosts in URLs, leading to an authorization bypass in some applications. This is related to a Host field with a suffix appearing in neither Hostname() nor Port(), and is related to a non-numeric port number. For example, an attacker can compose a crafted javascript:// URL that results in a hostname of google.com.

References

• https://nvd.nist.gov/vuln/detail/CVE-2019-14809
• golang/go#29098
• https://access.redhat.com/errata/RHSA-2019:3433
• https://groups.google.com/forum/#!topic/golang-announce/0uuMm1BwpHE
• https://groups.google.com/forum/#!topic/golang-announce/65QixT3tcmg
• https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/4BBP27PZGSY6OP6D26E5FW4GZKBFHNU7/
• https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/LYO6E3H34C346D2E443GLXK7OK6KIYIQ/
• https://seclists.org/bugtraq/2019/Aug/31
• https://www.debian.org/security/2019/dsa-4503
• http://lists.opensuse.org/opensuse-security-announce/2019-08/msg00076.html
• http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00002.html
• http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00011.html
• http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00021.html
• http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00038.html