CVE-2015-6289: Cisco IOS 15.5(3)M on Integrated Services Router (ISR) 800, 819, and 829 devices allows remote attackers to...

Security readout for executives and security teams

This issue can let a remote attacker make certain Cisco ISR routers consume memory by sending crafted TCP traffic to the SSH service. The business impact is availability: affected branch or edge routers could become unstable or stop serving traffic. The provided sources do not give a CVSS score. Organizations using Cisco IOS 15.5(3)M on Cisco ISR 800, 819, or 829 routers are the named exposure group. Risk is higher where SSH management is reachable from untrusted networks or broad internal segments. Prioritize where affected routers support critical branch, WAN, or remote-site connectivity. The issue is availability-focused, not described as data theft or code execution, but outage impact can still be material. Mitigation focus: Review Cisco advisory cisco-sa-20160620-isr for official fixed software and guidance.; Restrict SSH management access to trusted administration networks only.; Disable unnecessary SSH exposure on affected routers where operationally feasible..

Prepared

Jun 13, 2026, 14:22 UTC (UTC+00:00)

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