CVE-2013-5503: The UDP process in Cisco IOS XR 4.3.1 does not free packet memory upon detecting full packet queues, which...

Security readout for executives and security teams

CVE-2013-5503 is a denial-of-service flaw in Cisco IOS XR 4.3.1. A remote attacker can send UDP packets to listening ports and trigger memory consumption because packet memory is not freed when queues are full. The business risk is router instability or service disruption, not documented data theft. Exposure is most likely where Cisco IOS XR 4.3.1 devices have UDP listening ports reachable from untrusted or poorly filtered networks. The bundle does not identify other affected versions or products. Treat this as a high-priority availability risk for any exposed Cisco IOS XR 4.3.1 infrastructure. Prioritize internet-facing or shared-network routers first, and verify vendor remediation because the bundle does not provide fixed-version details. Mitigation focus: Check Cisco advisory cisco-sa-20131002-iosxr for the supported remediation path.; Identify and prioritize any Cisco IOS XR 4.3.1 devices.; Limit untrusted UDP reachability to router listening ports where operationally feasible..

Prepared

Jun 14, 2026, 15:32 UTC (UTC+00:00)

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.