CVE-2021-31353

HIGH

Juniper Junos OS and Junos OS Evolved - Denial of Service via BGP Update Injection

Title source: llm
STIX 2.1

Description

An Improper Handling of Exceptional Conditions vulnerability in Juniper Networks Junos OS and Junos OS Evolved allows an attacker to inject a specific BGP update, causing the routing protocol daemon (RPD) to crash and restart, leading to a Denial of Service (DoS). Continued receipt and processing of the BGP update will create a sustained Denial of Service (DoS) condition. This issue affects very specific versions of Juniper Networks Junos OS: 19.3R3-S2; 19.4R3-S3; 20.2 versions 20.2R2-S3 and later, prior to 20.2R3-S2; 20.3 versions 20.3R2 and later, prior to 20.3R3; 20.4 versions 20.4R2 and later, prior to 20.4R3; 21.1 versions prior to 21.1R2. Juniper Networks Junos OS 20.1 is not affected by this issue. This issue also affects Juniper Networks Junos OS Evolved: All versions prior to 20.4R2-S3-EVO, 20.4R3-EVO; 21.1-EVO versions prior to 21.1R2-EVO; 21.2-EVO versions prior to 21.2R2-EVO.

References (1)

Core 1
Core References
Exploit, Mitigation, Vendor Advisory x_refsource_confirm
https://kb.juniper.net/JSA11218

Scores

CVSS v3 7.5
EPSS 0.0041
EPSS Percentile 61.5%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Details

CWE
CWE-755
Status published
Products (10)
juniper/junos 19.3 r3-s2
juniper/junos 19.4 r3-s3
juniper/junos 20.2 r2-s3 (3 CPE variants)
juniper/junos 20.3 r2 (2 CPE variants)
juniper/junos 20.4 r2 (2 CPE variants)
juniper/junos 21.1 r1 (2 CPE variants)
juniper/junos_os_evolved 20.4 r1 (6 CPE variants)
juniper/junos_os_evolved 21.1 r1 (2 CPE variants)
juniper/junos_os_evolved 21.2 r1 (2 CPE variants)
juniper/junos_os_evolved < 20.3
Published Oct 19, 2021
Tracked Since Feb 18, 2026