CVE-2021-0237

/// Technical description

On Juniper Networks EX4300-MP Series, EX4600 Series, EX4650 Series, QFX5K Series deployed as a Virtual Chassis with a specific Layer 2 circuit configuration, Packet Forwarding Engine manager (FXPC) process may crash and restart upon receipt of specific layer 2 frames. Continued receipt and processing of this packet will create a sustained Denial of Service (DoS) condition. This issue affects: Juniper Networks Junos OS on EX4300-MP Series, EX4600 Series, EX4650 Series, QFX5K Series 15.1 versions prior to 15.1R7-S9; 17.3 versions prior to 17.3R3-S11; 17.4 versions prior to 17.4R2-S13, 17.4R3-S4, 17.4R3-S5; 18.2 versions prior to 18.2R3-S8; 18.3 versions prior to 18.3R3-S4; 18.4 versions prior to 18.4R2-S7, 18.4R3-S6; 19.1 versions prior to 19.1R3-S4; 19.2 versions prior to 19.2R1-S6, 19.2R3-S1; 19.3 versions prior to 19.3R3-S1; 19.4 versions prior to 19.4R2-S4, 19.4R3-S1; 20.1 versions prior to 20.1R2; 20.2 versions prior to 20.2R2, 20.2R3; 20.3 versions prior to 20.3R1-S2, 20.3R2;

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References