A security flaw was found in the way Yum package manager performed management of repository metadata in certain circumstances (bad metadata were not removed properly and re-used in subsequent run). An attacker could inject a specially-crafted Trojan horse file in the metadata of a remote repository, possibly leading to their ability to confuse Yum package manager to accept invalid untrusted metadata as valid by mistake.
This issue did NOT affect the versions of the yum package, as shipped with Red Hat Enterprise Linux 5 and 6.
This issue affects the versions of the yum package, as shipped with Fedora release of 17 and 18.
Relevant upstream patch:
This issue was found by James Antill of Red Hat.
This issue was corrected in the yum-3.4.3-31.fc17 package version for Fedora release of 17, and in the yum-3.4.3-51.fc18 package version for Fedora release of 18.
Not vulnerable. This issue did not affect the versions of yum as shipped with Red Hat Enterprise Linux 5 and 6, as yum in those products did not (try to) use filelists metadata yet.
Added CVE as per http://www.openwall.com/lists/oss-security/2013/03/29/4
Setting first statement as private, as it is ignored in favor of comment 8.