Created golang tracking bugs for this issue:
Affects: epel-all [bug 1743130]
Affects: fedora-all [bug 1743131]
The Go language has an utility which can be used to parse host name strings. The utility can be accessed by calling url.Parse(url) call and returns an object of type URL. This object has two different methods called Hostname() and Port(), those calls returns the hostname itself and the port number from the parsed url string. When url string is malformed the behavior of both calls above are unpredictable sometimes returning unexpected hostname values. An attacker can leverage this bug by crafting specially formatted invalid URL as input to url.Parse(), this will lead url.Hostname() calls to return a host name controlled by the attacker allowing authorization bypass and other consequences depending on how those calls are used.
This flaw has no mitigation for any affected golang package versions.
This issue has been addressed in the following products:
Red Hat Enterprise Linux 8
Via RHSA-2019:3433 https://access.redhat.com/errata/RHSA-2019:3433
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):