Junos OS: jdhcpd process crash when processing a specific DHCPDv6 packet in DHCPv6 relay configuration.

published 2020-10-16 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-12534

cvss: 7.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 1.0%; EPSS 1.0% chance of exploitation in 30 days, percentile 64%
public exploits: 0; none known

On Juniper Networks Junos OS devices configured with DHCPv6 relay enabled, receipt of a specific DHCPv6 packet might crash the jdhcpd daemon. The jdhcpd daemon automatically restarts without intervention, but continuous receipt of specific crafted DHCP messages will repeatedly crash jdhcpd, leading to an extended Denial of Service (DoS) condition. Only DHCPv6 packet can trigger this issue. DHCPv4 packet cannot trigger this issue. This issue affects Juniper Networks Junos OS: 17.3 versions prior to 17.3R3-S9; 17.4 versions prior to 17.4R2-S11, 17.4R3-S2, 17.4R3-S3; 18.1 versions prior to 18.1R3-S11; 18.2 versions prior to 18.2R3-S5; 18.3 versions prior to 18.3R2-S4, 18.3R3-S3; 18.4 versions prior to 18.4R2-S5, 18.4R3-S4; 19.1 versions prior to 19.1R2-S2, 19.1R3-S2; 19.2 versions prior to 19.2R1-S5, 19.2R2-S1, 19.2R3; 19.3 versions prior to 19.3R2-S4, 19.3R2-S4, 19.3R3; 19.4 versions prior to 19.4R1-S3, 19.4R2-S1, 19.4R3; 20.1 versions prior to 20.1R1-S3, 20.1R2.

Patch / fix

fixed in 1

Juniper Networks Junos OS 17.3R3-S9, 17.4R2-S11, 17.4R3-S2, 17.4R3-S3, 18.1R3-S11, 18.2R3-S5, 18.2X75-D34, 18.2X75-D65, 18.3R2-S4, 18.3R3-S3, 18.4R2-S5, 18.4R3-S4, 19.1R2-S2, 19.1R3-S2, 19.2R1-S5, 19.2R2-S1, 19.2R3, 19.3R2-S4, 19.3R2-S4, 19.3R3, 19.4R1-S3, 19.4R2-S1, 19.4R3, 20.1R1-S3, 20.1R2

Exploit prediction

1.04% chance of exploitation in the next 30 days, higher than 64% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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-20 Improper Input Validation

References

kb.juniper.net /JSA11069
vendor-advisory

Sources

CVE List CVE-2020-1672
NVD CVE-2020-1672

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Summary