Vulnerability Monitor

The vendors, products, and vulnerabilities you care about

CVE-2026-21919


An Incorrect Synchronization vulnerability in the management daemon (mgd) of Juniper Networks Junos OS and Junos OS Evolved allows a network-based attacker with low privileges to cause a complete Denial-of-Service (DoS) of the management plane. When NETCONF sessions are quickly established and disconnected, a locking issue causes mgd processes to hang in an unusable state. When the maximum number of mgd processes has been reached, no new logins are possible. This leads to the inability to manage the device and requires a power-cycle to recover. This issue can be monitored by checking for mgd processes in lockf state in the output of 'show system processes extensive': user@host> show system processes extensive | match mgd <pid> root       20   0 501M 4640K lockf   1 0:01 0.00% mgd If the system still can be accessed (either via the CLI or as root, which might still be possible as last resort as this won't invoke mgd), mgd processes in this state can be killed with 'request system process terminate <PID>' from the CLI or with 'kill -9 <PID>' from the shell.  This issue affects: Junos OS: * 23.4 versions before 23.4R2-S4, * 24.2 versions before 24.2R2-S1, * 24.4 versions before 24.4R1-S3, 24.4R2; This issue does not affect Junos OS versions before 23.4R1; Junos OS Evolved: * 23.4 versions before 23.4R2-S5-EVO, * 24.2 versions before 24.2R2-S1-EVO, * 24.4 versions before 24.4R1-S3-EVO, 24.4R2-EVO. This issue does not affect Junos OS Evolved versions before 23.4R1-EVO;


Security Impact Summary

This vulnerability carries a MEDIUM severity rating with a CVSS v3.1 score of 6.5, indicating it can be exploited remotely over the network with relatively low complexity without requiring user interaction requiring only low-level privileges . The vulnerability impacts and availability (service disruption) for affected systems. Impacting 2 products from juniper, from juniper organizations running these solutions should prioritize assessment and patching.

Historical Context

Reported in 2026, this vulnerability emerged during an era marked by increased sophistication in supply chain attacks, cloud infrastructure vulnerabilities, and software-as-a-service (SaaS) security challenges. Security practices during this period emphasized zero-trust architectures, container security, and API protection.


Published

2026-04-09T22:16:25.173

Last Modified

2026-06-17T10:19:09.803

Status

Analyzed

Source

[email protected]

Severity

CVSSv3.1: 6.5 (MEDIUM)

Weaknesses
  • Type: Secondary
    CWE-821

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 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
Operating System juniper junos_os_evolved 23.4 Yes
Operating System juniper junos_os_evolved 23.4 Yes
Operating System juniper junos_os_evolved 23.4 Yes
Operating System juniper junos_os_evolved 23.4 Yes
Operating System juniper junos_os_evolved 23.4 Yes
Operating System juniper junos_os_evolved 23.4 Yes
Operating System juniper junos_os_evolved 23.4 Yes
Operating System juniper junos_os_evolved 23.4 Yes
Operating System juniper junos_os_evolved 23.4 Yes
Operating System juniper junos_os_evolved 24.2 Yes
Operating System juniper junos_os_evolved 24.2 Yes
Operating System juniper junos_os_evolved 24.2 Yes
Operating System juniper junos_os_evolved 24.2 Yes
Operating System juniper junos_os_evolved 24.4 Yes
Operating System juniper junos_os_evolved 24.4 Yes
Operating System juniper junos_os_evolved 24.4 Yes
Operating System juniper junos_os_evolved 24.4 Yes

References

How SecUtils Interprets This CVE

SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For juniper's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.