CVE-2021-0229

Junos OS: Receipt of specific packets could lead to Denial of Service in MQTT Server

MEDIUM

5.3

CVSS Score

Published: April 22, 2021 at 07:36 PM UTC

Updated: June 17, 2026 at 03:29 AM UTC

1 product affected across 1 vendorJunos

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Severity

MEDIUM5.3

Exploit prediction

EPSS 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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Junos · Juniper Networks

95%

16.1R1 ≤ v < 16.1*17.3 ≤ v < 17.3R3-S1117.4 ≤ v < 17.4R2-S13, 17.4R3-S418.1 ≤ v < 18.1R3-S1218.2 ≤ v < 18.2R2-S8, 18.2R3-S718.3 ≤ v < 18.3R3-S418.4 ≤ v < 18.4R1-S8, 18.4R2-S7, 18.4R3-S719.1 ≤ v < 19.1R3-S519.2 ≤ v < 19.2R1-S6, 19.2R3-S219.3 ≤ v < 19.3R3-S219.4 ≤ v < 19.4R2-S4, 19.4R3-S220.1 ≤ v < 20.1R2-S1, 20.1R320.2 ≤ v < 20.2R2-S2, 20.2R320.3 ≤ v < 20.3R1-S1, 20.3R216.1 r1 16.1 r2 16.1 r3 16.1 r3-s10 16.1 r3-s11 16.1 r3-s8 16.1 r4 16.1 r4-s12 16.1 r4-s2 16.1 r4-s3 16.1 r4-s4 16.1 r4-s6 16.1 r4-s8 16.1 r4-s9 16.1 r5 16.1 r5-s4 16.1 r6 16.1 r6-s1 16.1 r6-s3 16.1 r6-s4 16.1 r6-s6 16.1 r7 16.1 r7-s2 16.1 r7-s3 16.1 r7-s4 16.1 r7-s5 16.1 r7-s6 16.1 r7-s7 16.1R1 16.2 16.2 r1 16.2 r1-s6 16.2 r2 16.2 r2-s1 16.2 r2-s10 16.2 r2-s2 16.2 r2-s5 16.2 r2-s6 16.2 r2-s7 16.2 r2-s8 16.2 r2-s9 16.2 r3 17.1 17.1 r1 17.1 r1-s7 17.1 r2 17.1 r2-s1 17.1 r2-s10 17.1 r2-s11 17.1 r2-s2 17.1 r2-s3 17.1 r2-s4 17.1 r2-s5 17.1 r2-s6 17.1 r2-s7 17.1 r2-s8 17.1 r2-s9 17.1 r3 17.1 r3-s1 17.2 17.2 r1 17.2 r1-s1 17.2 r1-s2 17.2 r1-s3 17.2 r1-s4 17.2 r1-s5 17.2 r1-s6 17.2 r1-s7 17.2 r1-s8 17.2 r2 17.2 r2-s11 17.2 r2-s4 17.2 r2-s6 17.2 r2-s7 17.2 r3 17.2 r3-s1 17.2 r3-s2 17.2 r3-s3 17.3 17.3 r1 17.3 r1-s1 17.3 r1-s4 17.3 r2 17.3 r2-s1 17.3 r2-s2 17.3 r2-s3 17.3 r2-s4 17.3 r2-s5 17.3 r3 17.3 r3-s1 17.3 r3-s10 17.3 r3-s2 17.3 r3-s3 17.3 r3-s4 17.3 r3-s5 17.3 r3-s6 17.3 r3-s7 17.3 r3-s8 17.3 r3-s9 17.4 17.4 r1 17.4 r1-s1 17.4 r1-s2 17.4 r1-s3 17.4 r1-s4 17.4 r1-s5 17.4 r1-s6 17.4 r1-s7 17.4 r2 17.4 r2-s1 17.4 r2-s10 17.4 r2-s11 17.4 r2-s12 17.4 r2-s2 17.4 r2-s3 17.4 r2-s4 17.4 r2-s5 17.4 r2-s6 17.4 r2-s7 17.4 r2-s8 17.4 r2-s9 17.4 r3 17.4 r3-s1 17.4 r3-s2 17.4 r3-s3 18.1 18.1 r1 18.1 r2 18.1 r2-s1 18.1 r2-s2 18.1 r2-s4 18.1 r3 18.1 r3-s1 18.1 r3-s10 18.1 r3-s11 18.1 r3-s2 18.1 r3-s3 18.1 r3-s4 18.1 r3-s5 18.1 r3-s6 18.1 r3-s7 18.1 r3-s8 18.1 r3-s9 18.2 18.2 r1 18.2 r1-s2 18.2 r1-s3 18.2 r1-s4 18.2 r1-s5 18.2 r2 18.2 r2-s1 18.2 r2-s2 18.2 r2-s3 18.2 r2-s4 18.2 r2-s5 18.2 r2-s6 18.2 r2-s7 18.2 r3 18.2 r3-s1 18.2 r3-s2 18.2 r3-s3 18.2 r3-s4 18.2 r3-s5 18.2 r3-s6 18.3 18.3 r1 18.3 r1-s1 18.3 r1-s2 18.3 r1-s3 18.3 r1-s4 18.3 r1-s5 18.3 r1-s6 18.3 r2 18.3 r2-s1 18.3 r2-s2 18.3 r2-s3 18.3 r2-s4 18.3 r3 18.3 r3-s1 18.3 r3-s2 18.3 r3-s3 18.4 18.4 r1 18.4 r1-s1 18.4 r1-s2 18.4 r1-s3 18.4 r1-s4 18.4 r1-s5 18.4 r1-s6 18.4 r1-s7 18.4 r2 18.4 r2-s1 18.4 r2-s2 18.4 r2-s3 18.4 r2-s4 18.4 r2-s5 18.4 r2-s6 18.4 r3 18.4 r3-s1 18.4 r3-s2 18.4 r3-s3 18.4 r3-s4 18.4 r3-s5 18.4 r3-s6 19.1 19.1 r1 19.1 r1-s1 19.1 r1-s2 19.1 r1-s3 19.1 r1-s4 19.1 r1-s5 19.1 r2 19.1 r2-s1 19.1 r3 19.1 r3-s1 19.1 r3-s2 19.1 r3-s3 19.1 r3-s4 19.2 19.2 r1 19.2 r1-s1 19.2 r1-s2 19.2 r1-s3 19.2 r1-s4 19.2 r1-s5 19.2 r2 19.2 r2-s1 19.2 r3 19.2 r3-s1 19.3 19.3 r1 19.3 r1-s1 19.3 r2 19.3 r2-s1 19.3 r2-s2 19.3 r2-s3 19.3 r2-s4 19.3 r2-s5 19.3 r3 19.4 19.4 r1 19.4 r1-s1 19.4 r1-s2 19.4 r2 19.4 r2-s1 19.4 r2-s2 19.4 r2-s3 19.4 r3 19.4 r3-s1 20.1 20.1 r1 20.1 r1-s1 20.1 r1-s2 20.1 r1-s3 20.1 r1-s4 20.2 20.2 r1 20.2 r1-s1 20.2 r1-s2 20.2 r2 20.2 r2-s1 20.3 20.3 r1

Affected range stops below 16.1*, so it looks safe — our inference, not a vendor statement

Affected range stops below 17.3R3-S11, so it looks safe — our inference, not a vendor statement

Affected range stops below 17.4R2-S13, 17.4R3-S4, so it looks safe — our inference, not a vendor statement

Affected range stops below 18.1R3-S12, so it looks safe — our inference, not a vendor statement

Affected range stops below 18.2R2-S8, 18.2R3-S7, so it looks safe — our inference, not a vendor statement

Affected range stops below 18.3R3-S4, so it looks safe — our inference, not a vendor statement

Affected range stops below 18.4R1-S8, 18.4R2-S7, 18.4R3-S7, so it looks safe — our inference, not a vendor statement

Affected range stops below 19.1R3-S5, so it looks safe — our inference, not a vendor statement

Affected range stops below 19.2R1-S6, 19.2R3-S2, so it looks safe — our inference, not a vendor statement

Affected range stops below 19.3R3-S2, so it looks safe — our inference, not a vendor statement

Affected range stops below 19.4R2-S4, 19.4R3-S2, so it looks safe — our inference, not a vendor statement

Affected range stops below 20.1R2-S1, 20.1R3, so it looks safe — our inference, not a vendor statement

Affected range stops below 20.2R2-S2, 20.2R3, so it looks safe — our inference, not a vendor statement

Affected range stops below 20.3R1-S1, 20.3R2, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

https://kb.juniper.net/JSA11124

References (1)

x_refsource_MISCVendor Advisory

Source: [email protected]

https://kb.juniper.net/JSA11124

CVSS

5.3MEDIUMjuniper

Attack Vector: NETWORK
Complexity: LOW
Privileges: NONE
User Interaction: NONE
Scope: UNCHANGED
Confidentiality: NONE
Integrity: NONE
Availability: LOW

Vector?

Quick Info

StatusMODIFIED

CWE

CWE-400

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