Race condition in Junos OS and Junos OS Evolved - CVE-2026-21919
Published: May 8, 2026
Vulnerability identifier: #VU130704
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-21919
CWE-ID: CWE-362
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Juniper Networks, Inc.
Affected software:
Junos OS
Junos OS Evolved
Junos OS
Junos OS Evolved
Detailed vulnerability description
The vulnerability allows a remote user to cause a denial of service.
The vulnerability exists due to incorrect synchronization in the management daemon (mgd) when handling rapid NETCONF session establishment and disconnection. A remote user can repeatedly connect and disconnect NETCONF sessions to cause a denial of service.
Only devices with NETCONF enabled are exposed. When the maximum number of mgd processes is reached, no new logins are possible, and recovery requires a power-cycle.
How to mitigate CVE-2026-21919
Install security update from vendor's website.