An Improper Input Validation vulnerability in the active-lease query portion in JDHCPD's DHCP Relay Agent of Juniper Networks Junos OS allows an attacker to cause a Denial of Service (DoS) by sending a crafted DHCP packet to the device thereby crashing the jdhcpd DHCP service. This is typically configured for Broadband Subscriber Sessions.

Continued receipt and processing of this crafted packet will create a sustained Denial of Service (DoS) condition.

This issue affects Juniper Networks Junos OS:

• 19.4 versions prior to 19.4R3-S1;
• 20.1 versions prior to 20.1R2-S1, 20.1R3;
• 20.2 versions prior to 20.2R3;
• 20.3 versions prior to 20.3R2.

This issue does not affect Junos OS Evolved.

This issue requires active-lease query with none or greater optional settings to be configured in one or more hierarchy locations.

with

Juniper SIRT is not aware of any malicious exploitation of this vulnerability.

This issue was seen during production usage.

This issue has been assigned  CVE-2021-0267 .

The following software releases have been updated to resolve this specific issue:

Junos OS: 19.4R3-S1, 20.1R2-S1, 20.1R3, 20.2R3, 20.3R2, 20.4R1, and all subsequent releases.

This issue is being tracked as  1534814 .

Software releases or updates are available for download at https://support.juniper.net/support/downloads/

There are no viable workarounds for this issue.

2021-04-14: Initial Publication.

• KB16613: Overview of the Juniper Networks SIRT Quarterly Security Bulletin Publication Process [juniper.net]
• KB16765: In which releases are vulnerabilities fixed? [juniper.net]
• KB16446: Common Vulnerability Scoring System (CVSS) and Juniper's Security Advisories [juniper.net]
• Report a Security Vulnerability - How to Contact the Juniper Networks Security Incident Response Team
• CVE-2021-0267 at cve.mitre.org
• TechLibrary | Junos OS | Broadband Subscriber Sessions User Guide | active-leasequery (DHCP Relay Agent)