CVE-2021-31369

Junos OS: MX Series: Traffic drops will be observed if MS-MPC/MS-PIC resources are consumed by certain traffic causing a partial DoS

MEDIUM

5.3

CVSS Score

Published: October 19, 2021 at 06:17 PM UTC

Updated: June 17, 2026 at 03:51 AM UTC

18 products affected across 2 vendorsJunosMx960Mx480

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Severity

MEDIUM5.3

Exploit prediction

EPSS 1.0%

Description

On MX Series platforms with MS-MPC/MS-MIC, an Allocation of Resources Without Limits or Throttling vulnerability in Juniper Networks Junos OS allows an unauthenticated network attacker to cause a partial Denial of Service (DoS) with a high rate of specific traffic. If a Class of Service (CoS) rule is attached to the service-set and a high rate of specific traffic is processed by this service-set, for some of the other traffic which has services applied and is being processed by this MS-MPC/MS-MIC drops will be observed. Continued receipted of this high rate of specific traffic will create a sustained Denial of Service (DoS) condition. This issue affects: Juniper Networks Junos OS on MX Series with MS-MPC/MS-MIC: All versions prior to 17.4R3-S5; 18.3 versions prior to 18.3R3-S5; 18.4 versions prior to 18.4R3-S9; 19.1 versions prior to 19.1R3-S6; 19.2 versions prior to 19.2R1-S7, 19.2R3-S3; 19.3 versions prior to 19.3R2-S7, 19.3R3-S3; 19.4 versions prior to 19.4R3-S5; 20.1 versions prior to 20.1R2-S2, 20.1R3-S1; 20.2 versions prior to 20.2R3-S2; 20.3 versions prior to 20.3R3; 20.4 versions prior to 20.4R2-S1, 20.4R3; 21.1 versions prior to 21.1R1-S1, 21.1R2.

Affected

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

Junos · Juniper Networks

95%

v < 17.4v < 17.4R3-S518.3 ≤ v < 18.3R3-S518.4 ≤ v < 18.4R3-S919.1 ≤ v < 19.1R3-S619.2 ≤ v < 19.2R1-S7, 19.2R3-S319.3 ≤ v < 19.3R2-S7, 19.3R3-S319.4 ≤ v < 19.4R3-S520.1 ≤ v < 20.1R2-S2, 20.1R3-S120.2 ≤ v < 20.2R3-S220.3 ≤ v < 20.3R320.4 ≤ v < 20.4R2-S1, 20.4R321.1 ≤ v < 21.1R1-S1, 21.1R217.4 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-s13 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 17.4 r3-s4 18.3 18.3 r 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 18.3 r3-s4 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 r2-s7 18.4 r2-s8 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 18.4 r3-s7 18.4 r3-s8 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 r1-s6 19.1 r2 19.1 r2-s1 19.1 r2-s2 19.1 r2-s3 19.1 r3 19.1 r3-s1 19.1 r3-s2 19.1 r3-s3 19.1 r3-s4 19.1 r3-s5 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 r1-s6 19.2 r3 19.2 r3-s1 19.2 r3-s2 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 r2-s6 19.3 r3 19.3 r3-s1 19.3 r3-s2 19.4 19.4 r1 19.4 r1-s1 19.4 r1-s2 19.4 r1-s3 19.4 r1-s4 19.4 r2 19.4 r2-s1 19.4 r2-s2 19.4 r2-s3 19.4 r2-s4 19.4 r2-s5 19.4 r3 19.4 r3-s1 19.4 r3-s2 19.4 r3-s3 19.4 r3-s4 20.1 20.1 r1 20.1 r1-s1 20.1 r1-s2 20.1 r1-s3 20.1 r1-s4 20.1 r2 20.1 r2-s1 20.1 r3 20.2 20.2 r1 20.2 r1-s1 20.2 r1-s2 20.2 r1-s3 20.2 r2 20.2 r2-s1 20.2 r2-s2 20.2 r2-s3 20.2 r3 20.2 r3-s1 20.3 20.3 r1 20.3 r1-s1 20.3 r2 20.3 r2-s1 20.4 20.4 r1 20.4 r1-s1 20.4 r2 21.1 21.1 r1

Affected range stops below 17.4, so it looks safe — our inference, not a vendor statement

Affected range stops below 17.4R3-S5, so it looks safe — our inference, not a vendor statement

Affected range stops below 18.3R3-S5, so it looks safe — our inference, not a vendor statement

Affected range stops below 18.4R3-S9, so it looks safe — our inference, not a vendor statement

Affected range stops below 19.1R3-S6, so it looks safe — our inference, not a vendor statement

Affected range stops below 19.2R1-S7, 19.2R3-S3, so it looks safe — our inference, not a vendor statement

Affected range stops below 19.3R2-S7, 19.3R3-S3, so it looks safe — our inference, not a vendor statement

Affected range stops below 19.4R3-S5, so it looks safe — our inference, not a vendor statement

Affected range stops below 20.1R2-S2, 20.1R3-S1, so it looks safe — our inference, not a vendor statement

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

Affected range stops below 20.3R3, so it looks safe — our inference, not a vendor statement

Affected range stops below 20.4R2-S1, 20.4R3, so it looks safe — our inference, not a vendor statement

Affected range stops below 21.1R1-S1, 21.1R2, so it looks safe — our inference, not a vendor statement

juniper-mx10 (environment) · juniper-mx10000 (environment) · juniper-mx10003 (environment) · juniper-mx10008 (environment) · juniper-mx10016 (environment) · juniper-mx104 (environment) · juniper-mx150 (environment) · juniper-mx2008 (environment) · juniper-mx2010 (environment) · juniper-mx2020 (environment) · juniper-mx204 (environment) · juniper-mx240 (environment) · juniper-mx40 (environment) · juniper-mx480 (environment) · juniper-mx5 (environment) · juniper-mx80 (environment) · juniper-mx960 (environment)

Mx10 · Juniperdevice

80%

All versions

Mx10000 · Juniperdevice

80%

All versions

Mx10003 · Juniperdevice

80%

All versions

Mx10008 · Juniperdevice

80%

All versions