By flooding a router with specially crafted IPv6 traffic, all available resources can be consumed, leading to the inability to store next hop information for legitimate traffic. In extreme cases, the crafted IPv6 traffic may result in a total resource exhaustion and kernel panic. The issue is triggered by traffic destined to the router. Transit traffic does not trigger the vulnerability. This issue only affects devices with IPv6 enabled and configured. Devices not configured to process IPv6 traffic are unaffected by this vulnerability. This issue was found during internal product security testing. Juniper SIRT is not aware of any malicious exploitation of this vulnerability. This issue has been assigned CVE-2016-4921 .
The kernel panic (PR 1017099) has been addressed in Junos OS 11.4R13, 12.1X44-D45, 12.1X46-D30, 12.1X47-D20, 12.3R9, 13.3R5, and all software releases listed below. However, a more complete IPv6 resource management improvement (PR 1037225) has addressed these resource exhaustion issues in the following software releases: 11.4R13-S3, 12.3R3-S4, 12.3X48-D30, 13.3R10*, 13.3R4-S11, 14.1R2-S8, 14.1R4-S12, 14.1R8, 14.1X53-D28, 14.1X53-D40, 14.1X55-D35, 14.2R3-S10, 14.2R4-S7, 14.2R6, 15.1F2-S5, 15.1F5-S2, 15.1F6, 15.1R3, 15.1X49-D40, 15.1X53-D57, 15.1X53-D70, 16.1R1, and all subsequent releases. The two fixes for this issue are being tracked as PRs 1037225 and 1017099 which are visible on the Customer Support website. KB16765 [juniper.net] - "In which releases are vulnerabilities fixed?" describes which release vulnerabilities are fixed as per our End of Engineering and End of Life support policies. *Available end of Q4/2016.
Limit the exploitable attack surface of critical infrastructure networking equipment. Use access lists or firewall filters to limit access to the router via IPv6 only from trusted, administrative networks or hosts.
2016-10-12: Initial publication 2016-10-17: Added fixes for 14.1X53-D28, 14.1X55-D35, and 15.1X53-D61 2017-08-07: Additional fixed releases