CVE-2021-0229

MEDIUM

Juniper Junos OS DoS via MQTT Packet Stream

Title source: llm
STIX 2.1

Description

An uncontrolled resource consumption vulnerability in Message Queue Telemetry Transport (MQTT) server of Juniper Networks Junos OS allows an attacker to cause MQTT server to crash and restart leading to a Denial of Service (DoS) by sending a stream of specific packets. A Juniper Extension Toolkit (JET) application designed with a listening port uses the Message Queue Telemetry Transport (MQTT) protocol to connect to a mosquitto broker that is running on Junos OS to subscribe for events. Continued receipt and processing of this packet will create a sustained Denial of Service (DoS) condition. This issue affects Juniper Networks Junos OS: 16.1R1 and later versions prior to 17.3R3-S11; 17.4 versions prior to 17.4R2-S13, 17.4R3-S4; 18.1 versions prior to 18.1R3-S12; 18.2 versions prior to 18.2R2-S8, 18.2R3-S7; 18.3 versions prior to 18.3R3-S4; 18.4 versions prior to 18.4R1-S8, 18.4R2-S7, 18.4R3-S7; 19.1 versions prior to 19.1R3-S5; 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-S2; 20.1 versions prior to 20.1R2-S1, 20.1R3; 20.2 versions prior to 20.2R2-S2, 20.2R3; 20.3 versions prior to 20.3R1-S1, 20.3R2. This issue does not affect Juniper Networks Junos OS versions prior to 16.1R1.

References (1)

Core 1
Core References
Vendor Advisory x_refsource_misc
https://kb.juniper.net/JSA11124

Scores

CVSS v3 5.3
EPSS 0.0053
EPSS Percentile 67.2%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Details

CWE
CWE-400
Status published
Products (3)
juniper/junos 16.1 r1 (28 CPE variants)
juniper/junos 16.2 (13 CPE variants)
juniper/junos 17.1 (9 CPE variants)
Published Apr 22, 2021
Tracked Since Feb 18, 2026