Due to an improper check for unusual or exceptional conditions in Juniper Networks Junos OS and Junos OS Evolved the Routing Protocol Daemon (RPD) service, upon receipt of a specific matching BGP packet meeting a specific term in the flowspec configuration, crashes and restarts causing a Denial of Service (DoS). Continued receipt and processing of this packet will create a sustained Denial of Service (DoS) condition.

This issue affects only Multiprotocol BGP (MP-BGP) VPNv6 FlowSpec deployments.

This issue affects:

Juniper Networks Junos OS:

• 18.4 versions prior to 18.4R1-S8, 18.4R2-S7, 18.4R3-S7;
• 19.1 versions prior to 19.1R2-S2, 19.1R3-S4;
• 19.2 versions prior to 19.2R1-S6, 19.2R3-S2;
• 19.3 versions prior to 19.3R3-S2;
• 19.4 versions prior to 19.4R2-S4, 19.4R3-S1;
• 20.1 versions prior to 20.1R2, 20.1R3;
• 20.2 versions prior to 20.2R2, 20.2R3;
• 20.3 versions prior to 20.3R1-S1, 20.3R2.

Juniper Networks Junos OS Evolved:

• All versions after 18.4R1-EVO prior to 20.3R2-EVO.

This issue does not affect:

Juniper Networks Junos OS versions prior to 18.4R1.

Juniper Networks Junos OS Evolved versions prior to 18.4R1-EVO.

The examples of the config stanza affected by this issue:

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

This issue was found during internal product security testing or research.

This issue has been assigned CVE-2021-0236 .

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

Junos OS: 18.4R1-S8, 18.4R2-S7, 18.4R3-S7, 19.1R2-S2, 19.1R3-S4, 19.2R1-S6, 19.2R3-S2, 19.3R3-S2, 19.4R2-S4, 19.4R3-S1, 20.1R2, 20.1R3, 20.2R2, 20.2R3, 20.3R1-S1, 20.3R2, 20.4R1 and all subsequent releases.

Junos OS Evolved: 20.3R2-EVO, 20.4R1-EVO, and all subsequent releases.

This issue is being tracked as 1537085 .

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

Do not configure "family inet6-vpn flow" under BGP if no inet6-vpn routes are required to be received.

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-2021-0236 at cve.mitre.org