Vulnerability Monitor

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CVE-2026-21920

An Unchecked Return Value vulnerability in the DNS module of Juniper Networks Junos OS on SRX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS). If an SRX Series device configured for DNS processing, receives a specifically formatted DNS request flowd will crash and restart, which causes a service interruption until the process has recovered. This issue affects Junos OS on SRX Series: * 23.4 versions before 23.4R2-S5, * 24.2 versions before 24.2R2-S1, * 24.4 versions before 24.4R2. This issue does not affect Junos OS versions before 23.4R1.

Published

2026-01-15T21:16:08.217

Last Modified

2026-01-23T18:51:59.987

Status

Analyzed

Source

[email protected]

Severity

CVSSv3.1: 7.5 (HIGH)

Weaknesses
  • Type: Primary
    CWE-252
Affected Vendors & Products
Type Vendor Product Version/Range Vulnerable?
Operating System juniper junos 23.4 Yes
Operating System juniper junos 23.4 Yes
Operating System juniper junos 23.4 Yes
Operating System juniper junos 23.4 Yes
Operating System juniper junos 23.4 Yes
Operating System juniper junos 23.4 Yes
Operating System juniper junos 23.4 Yes
Operating System juniper junos 23.4 Yes
Operating System juniper junos 23.4 Yes
Operating System juniper junos 24.2 Yes
Operating System juniper junos 24.2 Yes
Operating System juniper junos 24.2 Yes
Operating System juniper junos 24.2 Yes
Operating System juniper junos 24.2 Yes
Operating System juniper junos 24.4 Yes
Operating System juniper junos 24.4 Yes
Operating System juniper junos 24.4 Yes
Operating System juniper junos 24.4 Yes
Hardware juniper srx1500 - No
Hardware juniper srx1600 - No
Hardware juniper srx2300 - No
Hardware juniper srx300 - No
Hardware juniper srx320 - No
Hardware juniper srx340 - No
Hardware juniper srx345 - No
Hardware juniper srx380 - No
Hardware juniper srx4100 - No
Hardware juniper srx4120 - No
Hardware juniper srx4200 - No
Hardware juniper srx4300 - No
Hardware juniper srx4600 - No
Hardware juniper srx4700 - No
Hardware juniper srx5400 - No
Hardware juniper srx5600 - No
Hardware juniper srx5800 - No
References