CVE-2016-4921: Junos: IPv6 denial of service vulnerability due to resource exhaustion (CVE-2016-4921)

Security readout for executives and security teams

A vulnerable Junos router can be knocked offline or degraded by crafted IPv6 traffic sent directly to the router. The business impact is availability loss on affected routing infrastructure, potentially including outages if resources are exhausted or the kernel panics. Exposure is limited to Juniper Networks Junos OS devices on listed vulnerable releases that are configured to process IPv6 traffic directed at the router. Devices without IPv6 enabled or configured are stated as unaffected. Prioritize remediation for internet-facing or untrusted-network Junos routers with IPv6 enabled. The issue is high severity because it can affect routing availability, but urgency is moderated by no cited active exploitation and a configuration-specific exposure condition. Mitigation focus: Inventory Junos routers and identify releases listed as affected in the Juniper advisory.; Upgrade affected devices to the fixed Junos release specified for each branch, or later vendor-supported release.; If IPv6 is unnecessary, disable IPv6 processing according to Juniper-supported operational guidance..

Prepared

May 24, 2026, 09:27 UTC (UTC+00:00)

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