CVE-2021-31354

HIGH

Juniper Junos - Out-of-Bounds Read

Title source: rule
STIX 2.1

Description

An Out Of Bounds (OOB) access vulnerability in the handling of responses by a Juniper Agile License (JAL) Client in Juniper Networks Junos OS and Junos OS Evolved, configured in Network Mode (to use Juniper Agile License Manager) may allow an attacker to cause a partial Denial of Service (DoS), or lead to remote code execution (RCE). The vulnerability exists in the packet parsing logic on the client that processes the response from the server using a custom protocol. An attacker with control of a JAL License Manager, or with access to the local broadcast domain, may be able to spoof a new JAL License Manager and/or craft a response to the Junos OS License Client, leading to exploitation of this vulnerability. This issue only affects Junos systems configured in Network Mode. Systems that are configured in Standalone Mode (the default mode of operation for all systems) are not vulnerable to this issue. This issue affects: Juniper Networks Junos OS: 19.2 versions prior to 19.2R3-S3; 19.3 versions prior to 19.3R3-S3; 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; 20.4 versions prior to 20.4R3; 21.1 versions prior to 21.1R2. Juniper Networks Junos OS Evolved: version 20.1R1-EVO and later versions, prior to 21.2R2-EVO. This issue does not affect Juniper Networks Junos OS versions prior to 19.2R1.

References (1)

Core 1
Core References
Vendor Advisory x_refsource_confirm
https://kb.juniper.net/JSA11219

Scores

CVSS v3 7.1
EPSS 0.0028
EPSS Percentile 51.3%
Attack Vector ADJACENT_NETWORK
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L

Details

CWE
CWE-125
Status published
Products (6)
juniper/junos 19.2 (13 CPE variants)
juniper/junos 19.3 (12 CPE variants)
juniper/junos 20.1 r1 (8 CPE variants)
juniper/junos 20.2 r1 (10 CPE variants)
juniper/junos 20.3 r1 (4 CPE variants)
juniper/junos 20.4 r1 (3 CPE variants)
Published Oct 19, 2021
Tracked Since Feb 18, 2026