CVE-2021-31367

MEDIUM

Juniper Junos - Denial of Service via BGP FlowSpec Packet Memory Leak

Title source: llm
STIX 2.1

Description

A Missing Release of Memory after Effective Lifetime vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS on PTX Series allows an adjacent attacker to cause a Denial of Service (DoS) by sending genuine BGP flowspec packets which cause an FPC heap memory leak. Once having run out of memory the FPC will crash and restart along with a core dump. Continued receipted of these packets will create a sustained Denial of Service (DoS) condition. This issue affects: Juniper Networks Junos OS All versions prior to 18.4R3-S9; 19.1 versions prior to 19.1R3-S7; 19.2 versions prior to 19.2R1-S7, 19.2R3-S3; 19.3 versions prior to 19.3R2-S6, 19.3R3-S3; 19.4 versions prior to 19.4R1-S4, 19.4R3-S6; 20.1 versions prior to 20.1R2-S2, 20.1R3; 20.2 versions prior to 20.2R3-S1; 20.3 versions prior to 20.3R3; 20.4 versions prior to 20.4R3; 21.1 versions prior to 21.1R2. Juniper Networks Junos Evolved is not affected.

References (1)

Core 1
Core References
Patch, Vendor Advisory x_refsource_confirm
https://kb.juniper.net/JSA11229

Scores

CVSS v3 6.5
EPSS 0.0008
EPSS Percentile 23.6%
Attack Vector ADJACENT_NETWORK
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Details

CWE
CWE-401
Status published
Products (3)
juniper/junos 18.4 (27 CPE variants)
juniper/junos 19.1 (18 CPE variants)
juniper/junos 19.2 (5 CPE variants)
Published Oct 19, 2021
Tracked Since Feb 18, 2026