CVE-2013-1166: Cisco IOS XE 3.2 through 3.4 before 3.4.5S, and 3.5 through 3.7 before 3.7.1S, on 1000 series Aggregation S...

Security readout for executives and security teams

This flaw affects Cisco ASR 1000 routers running specific older IOS XE releases when both VRF-aware NAT and SIP ALG are enabled. A remote attacker could trigger repeated processing of SIP traffic and cause a router card reload, creating a denial of service. The business risk is network disruption, not data theft. Exposure is limited to Cisco ASR 1000 deployments running the named IOS XE trains with VRF-aware NAT and SIP ALG enabled. Internet, partner, or untrusted VoIP-facing edges would be more exposed than isolated internal routers. Treat as a high operational availability issue for affected ASR 1000 routers. It is old and configuration-specific, but a successful attack can disrupt routing services. Prioritize validation on exposed or business-critical network edges. Mitigation focus: Upgrade affected IOS XE releases to Cisco-fixed versions identified in the advisory.; Prioritize ASR 1000 routers carrying voice, edge, or high-availability traffic.; Check Cisco guidance for supported interim workarounds if immediate upgrade is not possible..

Prepared

Jun 24, 2026, 11:46 UTC (UTC+00:00)

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