CVE-2011-3280: Memory leak in the NAT implementation in Cisco IOS 12.1 through 12.4 and 15.0 through 15.1, and IOS XE 3.1....

Security readout for executives and security teams

This vulnerability affects Cisco routers using NAT on listed IOS and IOS XE releases. A remote attacker could send specially crafted SIP traffic to UDP port 5060 and exhaust memory, potentially forcing a device reload. The practical impact is network disruption rather than confirmed data compromise. Exposure is most likely on legacy Cisco IOS or IOS XE devices that run NAT and can receive SIP traffic on UDP/5060 from untrusted networks, partners, or the internet. Prioritize if legacy Cisco NAT routers support critical connectivity or voice-adjacent traffic. A successful attack can cause outage by consuming memory or reloading the device. There is no source-backed evidence here of active exploitation, so urgency should be exposure-driven. Mitigation focus: Identify Cisco IOS and IOS XE devices within the listed version ranges.; Review the Cisco advisory for affected configurations, fixed releases, and vendor workarounds.; Restrict untrusted SIP traffic to UDP/5060 where business requirements allow..

Prepared

Jun 27, 2026, 17:48 UTC (UTC+00:00)

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