Junos OS: MX Series: MS-MPC/MIC might crash when processing malformed IPv6 packet in NAT64 configuration.

published 2020-10-16 6y ago modified 2026-06-17 4mo ago also EUVD-2020-12542

cvss: 5.3; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 1.3%; EPSS 1.3% chance of exploitation in 30 days, percentile 70%
public exploits: 0; none known

On Juniper Networks MX Series with MS-MIC or MS-MPC card configured with NAT64 configuration, receipt of a malformed IPv6 packet may crash the MS-PIC component on MS-MIC or MS-MPC. This issue occurs when a multiservice card is translating the malformed IPv6 packet to IPv4 packet. An unauthenticated attacker can continuously send crafted IPv6 packets through the device causing repetitive MS-PIC process crashes, resulting in an extended Denial of Service condition. This issue affects Juniper Networks Junos OS on MX Series: 15.1 versions prior to 15.1R7-S7; 15.1X53 versions prior to 15.1X53-D593; 16.1 versions prior to 16.1R7-S8; 17.2 versions prior to 17.2R3-S4; 17.3 versions prior to 17.3R3-S6; 17.4 versions prior to 17.4R2-S11, 17.4R3; 18.1 versions prior to 18.1R3-S11; 18.2 versions prior to 18.2R3-S6; 18.2X75 versions prior to 18.2X75-D41, 18.2X75-D430, 18.2X75-D53, 18.2X75-D65; 18.3 versions prior to 18.3R2-S4, 18.3R3; 18.4 versions prior to 18.4R2-S5, 18.4R3; 19.1 versions prior to 19.1R2; 19.2 versions prior to 19.2R1-S5, 19.2R2; 19.3 versions prior to 19.3R2.

Patch / fix

fixed in 1

Juniper Networks Junos OS 15.1R7-S7, 15.1X53-D593, 16.1R7-S8, 17.2R3-S4, 17.3R3-S6, 17.4R2-S11, 17.4R3, 18.1R3-S11, 18.2R3-S6, 18.2X75-D41, 18.2X75-D430, 18.2X75-D53, 18.2X75-D65, 18.3R2-S4, 18.3R3, 18.4R2-S5, 18.4R3, 19.1R2, 19.2R1-S5, 19.2R2, 19.3R2

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Exploit prediction

1.31% chance of exploitation in the next 30 days, higher than 70% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by	version	score	vector
CNA	3.1	5.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
NVD	2.0	5.0	AV:N/AC:L/Au:N/C:N/I:N/A:P

Affected products

Juniper Networks Junos OS

Classification

Weakness

CWE-131 Incorrect Calculation of Buffer Size

References

kb.juniper.net /JSA11077
vendor-advisory

Sources

CVE List CVE-2020-1680
NVD CVE-2020-1680

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