A vulnerability was found in mod_auth_mellon. An open redirect in the logout URL allows requests with backslashes to pass through by assuming that it is a relative URL, while the browsers silently convert backslash characters into forward slashes using treating them as an absolute URL. This mismatch allows an attacker to bypass the redirect URL validation logic in apr_uri_parse function.
Upstream issue: https://github.com/Uninett/mod_auth_mellon/issues/35
Upstream Patch: https://github.com/Uninett/mod_auth_mellon/commit/62041428a32de402e0be6ba45fe12df6a83bedb8
Created mod_auth_mellon tracking bugs for this issue: Affects: fedora-all [bug 1691771]
This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2019:0766 https://access.redhat.com/errata/RHSA-2019:0766
This issue has been addressed in the following products: Red Hat Enterprise Linux 8 Via RHSA-2019:3421 https://access.redhat.com/errata/RHSA-2019:3421