CVE-2021-31371

MEDIUM

Juniper Junos OS Multiple Versions - Unauthenticated Sensitive Information Exposure

Title source: llm
STIX 2.1

Description

Juniper Networks Junos OS uses the 128.0.0.0/2 subnet for internal communications between the RE and PFEs. It was discovered that packets utilizing these IP addresses may egress an QFX5000 Series switch, leaking configuration information such as heartbeats, kernel versions, etc. out to the Internet, leading to an information exposure vulnerability. This issue affects Juniper Networks Junos OS on QFX5110, QFX5120, QFX5200, QFX5210 Series, and QFX5100 with QFX 5e Series image installed: All versions prior to 17.3R3-S12; 18.1 versions prior to 18.1R3-S13; 18.3 versions prior to 18.3R3-S5; 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-S6, 19.3R3-S3; 19.4 versions prior to 19.4R1-S4, 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-S1; 20.4 versions prior to 20.4R2-S1, 20.4R3; 21.1 versions prior to 21.1R1-S1, 21.1R2;

References (1)

Core 1
Core References
Mitigation, Vendor Advisory x_refsource_confirm
https://kb.juniper.net/JSA11236

Scores

CVSS v3 5.3
EPSS 0.0022
EPSS Percentile 43.9%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Details

CWE
CWE-200
Status published
Products (3)
juniper/junos 17.3 (22 CPE variants)
juniper/junos 18.1 (19 CPE variants)
juniper/junos 18.3 (9 CPE variants)
Published Oct 19, 2021
Tracked Since Feb 18, 2026