CVE-2016-4921
Junos: IPv6 denial of service vulnerability due to resource exhaustion (CVE-2016-4921)
- Published
- Updated
- Reserved
- Assigned by
- juniper
Description
By flooding a Juniper Networks router running Junos OS 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. Affected releases are Juniper Networks Junos OS 11.4 prior to 11.4R13-S3; 12.3 prior to 12.3R3-S4; 12.3X48 prior to 12.3X48-D30; 13.3 prior to 13.3R10, 13.3R4-S11; 14.1 prior to 14.1R2-S8, 14.1R4-S12, 14.1R8; 14.1X53 prior to 14.1X53-D28, 14.1X53-D40; 14.1X55 prior to 14.1X55-D35; 14.2 prior to 14.2R3-S10, 14.2R4-S7, 14.2R6; 15.1 prior to 15.1F2-S5, 15.1F5-S2, 15.1F6, 15.1R3; 15.1X49 prior to 15.1X49-D40; 15.1X53 prior to 15.1X53-D57, 15.1X53-D70.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| juniperCNA (assigner) | 3.0 | High7.5 | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| NVDNVD · Modified | 3.0 | High7.5 | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 2.9% · top 13% of all CVEs (3 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.
Weakness
- denial of service vulnerability
- CWE-399 (opens in a new tab)All about CWE-399 and its CVEs
Affected products
- affected 11.4 prior to 11.4R13-S3
- affected 12.3 prior to 12.3R3-S4
- affected 12.3X48 prior to 12.3X48-D30
- affected 13.3 prior to 13.3R10, 13.3R4-S11
- affected 14.1 prior to 14.1R2-S8, 14.1R4-S12, 14.1R8
- affected 14.1X53 prior to 14.1X53-D28, 14.1X53-D40
- affected 14.1X55 prior to 14.1X55-D35
- affected 14.2 prior to 14.2R3-S10, 14.2R4-S7, 14.2R6
- affected 15.1 prior to 15.1F2-S5, 15.1F5-S2, 15.1F6, 15.1R3
- affected 15.1X49 prior to 15.1X49-D40
- affected 15.1X53 prior to 15.1X53-D57, 15.1X53-D70
What to do
Workaround: 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.
References (3)
- https://kb.juniper.net/JSA10762 (opens in a new tab)x_refsource_CONFIRMx_transferred
- 1037014 (opens in a new tab)vdb-entryx_refsource_SECTRACKx_transferred
- 93532 (opens in a new tab)vdb-entryx_refsource_BIDx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2016-4921)Record last updated .