Junos OS Evolved: Receipt of a specifically malformed NDP packet could lead to Denial of Service

published 2020-10-16 6y ago modified 2026-06-17 4mo ago also EUVD-2020-12543

cvss: 6.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.5%; EPSS 0.5% chance of exploitation in 30 days, percentile 43%
public exploits: 0; none known

Receipt of a specifically malformed NDP packet sent from the local area network (LAN) to a device running Juniper Networks Junos OS Evolved can cause the ndp process to crash, resulting in a Denial of Service (DoS). The process automatically restarts without intervention, but a continuous receipt of the malformed NDP packets could leaded to an extended Denial of Service condition. During this time, IPv6 neighbor learning will be affected. The issue occurs when parsing the incoming malformed NDP packet. Rather than simply discarding the packet, the process asserts, performing a controlled exit and restart, thereby avoiding any chance of an unhandled exception. Exploitation of this vulnerability is limited to a temporary denial of service, and cannot be leveraged to cause additional impact on the system. This issue is limited to the processing of IPv6 NDP packets. IPv4 packet processing cannot trigger, and is unaffected by this vulnerability. This issue affects all Juniper Networks Junos OS Evolved versions prior to 20.1R2-EVO. Junos OS is unaffected by this vulnerability.

Patch / fix

fixed in 1

Juniper Networks Junos OS Evolved 20.1R2-EVO

Is CVE-2020-1681 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

Exploit prediction

0.51% chance of exploitation in the next 30 days, higher than 43% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by	version	score	vector
CNA	3.1	6.5	CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD	2.0	3.3	AV:A/AC:L/Au:N/C:N/I:N/A:P

Affected products

Juniper Networks Junos OS Evolved

Classification

Weakness

CWE-755 Improper Handling of Exceptional Conditions
CWE-617 Reachable Assertion

References

kb.juniper.net /JSA11078
vendor-advisory

Sources

CVE List CVE-2020-1681
NVD CVE-2020-1681

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.