yum does not properly handle bad metadata, which allows an attacker to cause a denial of service and possibly have other unspecified impact via a Trojan horse file in the metadata of a remote repository.
https://security-tracker.debian.org/tracker/CVE-2013-1910
https://exchange.xforce.ibmcloud.com/vulnerabilities/83348
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2013-1910
https://access.redhat.com/security/cve/cve-2013-1910