CVE-2021-31383

high-risk
Published 2021-10-19

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.

Do I need to act?

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0.46% chance of exploitation
EPSS score — low exploit probability
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
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Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
7
CVSS 7.5/10 High
NETWORK / LOW complexity

Affected Vendors

References (2)

56
/ 100
high-risk
Severity 26/34 · High
Exploitability 2/34 · Minimal
Exposure 28/34 · Critical