api/metadata/handler.py in OpenStack Compute (Nova) before 2013.2.4, 2014.x before 2014.1.2, and Juno before Juno-2, when proxying metadata requests through Neutron, makes it easier for remote attackers to guess instance ID signatures via a brute-force attack that relies on timing differences in responses to instance metadata requests.
www.openwall.com/lists/oss-security/2014/07/17/2
access.redhat.com/errata/RHSA-2014:0940
access.redhat.com/errata/RHSA-2014:1084
access.redhat.com/security/cve/CVE-2014-3517
bugs.launchpad.net/nova/+bug/1325128
bugzilla.redhat.com/show_bug.cgi?id=1112499
github.com/advisories/GHSA-xjmj-p278-4jp5
nvd.nist.gov/vuln/detail/CVE-2014-3517