CVE-2021-31383

Junos OS and Junos OS Evolved: In Point to MultiPoint (P2MP) scenarios receipt of various crafted packets causes RPD to core.

HIGH

7.5

CVSS Score

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

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

3 products affected across 2 vendorsJunosJunos OS EvolvedJunos OS Evolved

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Severity

HIGH7.5

Exploit prediction

EPSS 1%

Description

In Point to MultiPoint (P2MP) scenarios within established sessions between network or adjacent neighbors the improper use of a source to destination copy write operation combined with a Stack-based Buffer Overflow on certain specific packets processed by the routing protocol daemon (RPD) of Juniper Networks Junos OS and Junos OS Evolved sent by a remote unauthenticated network attacker causes the RPD to crash causing a Denial of Service (DoS). Continued receipt and processing of these packets will create a sustained Denial of Service (DoS) condition. This issue affects: Juniper Networks Junos OS 19.2 versions prior to 19.2R3-S2; 19.3 versions prior to 19.3R2-S6, 19.3R3-S2; 19.4 versions prior to 19.4R1-S4, 19.4R2-S4, 19.4R3-S3; 20.1 versions prior to 20.1R2-S2, 20.1R3; 20.2 versions prior to 20.2R2-S3, 20.2R3; 20.3 versions prior to 20.3R2. This issue does not affect Juniper Networks Junos OS versions prior to 19.2R1. Juniper Networks Junos OS Evolved 20.1 versions prior to 20.1R3-EVO; 20.2 versions prior to 20.2R3-EVO; 20.3 versions prior to 20.3R2-EVO.

Affected

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

Junos OS Evolved · Juniper

95%

20.1 20.1 r1 20.1 r1-s1 20.1 r2 20.1 r2-s1 20.1 r2-s2 20.1 r2-s3 20.1 r2-s4 20.1 r2-s5 20.2 20.2 r1 20.2 r1-s1 20.2 r2 20.2 r2-s1 20.3 20.3 r1 20.3 r1-s1 20.3 r1-s2 20.3 r1-s3

Junos · Juniper Networks

95%

19.2 ≤ v < 19.2R3-S219.3 ≤ v < 19.3R2-S6, 19.3R3-S219.4 ≤ v < 19.4R1-S4, 19.4R2-S4, 19.4R3-S320.1 ≤ v < 20.1R2-S2, 20.1R320.2 ≤ v < 20.2R2-S3, 20.2R320.3 ≤ v < 20.3R219.2 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 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 19.3 r3-s1 19.4 19.4 r1 19.4 r1-s1 19.4 r1-s2 19.4 r1-s3 19.4 r2 19.4 r2-s1 19.4 r2-s2 19.4 r2-s3 19.4 r3 19.4 r3-s1 19.4 r3-s2 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 20.2 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 20.3 20.3 r1 20.3 r1-s1

Vendor states this is fixed in 19.2R1 (unaffected)

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

Affected range stops below 19.3R2-S6, 19.3R3-S2, so it looks safe — our inference, not a vendor statement

Affected range stops below 19.4R1-S4, 19.4R2-S4, 19.4R3-S3, so it looks safe — our inference, not a vendor statement

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

Affected range stops below 20.2R2-S3, 20.2R3, so it looks safe — our inference, not a vendor statement

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

Junos OS Evolved · Juniper Networks

60%

20.1 ≤ v < 20.1R3-EVO20.2 ≤ v < 20.2R3-EVO20.3 ≤ v < 20.3R2-EVO20.1 20.2 20.3

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

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

Affected range stops below 20.3R2-EVO, 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/JSA11251

References (1)

x_refsource_CONFIRMVendor Advisory

Source: [email protected]

https://kb.juniper.net/JSA11251

CVSS

7.5HIGHjuniper

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

Vector?

Quick Info

StatusMODIFIED

CWE

CWE-121CWE-787

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