Vulnerability Database

320,453

Total vulnerabilities in the database

CVE-2026-21921

A Use After Free vulnerability in the chassis daemon (chassisd) of Juniper Networks Junos OS and Junos OS Evolved allows a network-based attacker authenticated with low privileges to cause a Denial-of-Service (DoS).

When telemetry collectors are frequently subscribing and unsubscribing to sensors continuously over a long period of time, telemetry-capable processes like chassisd, rpd or mib2d will crash and restart, which - depending on the process - can cause a complete outage until the system has recovered.

This issue affects:

 Junos OS: 

  • all versions before 22.4R3-S8,
  • 23.2 versions before 23.2R2-S5,
  • 23.4 versions before 23.4R2;

Junos OS Evolved:

  • all versions before 22.4R3-S8-EVO,
  • 23.2 versions before 23.2R2-S5-EVO,
  • 23.4 versions before 23.4R2-EVO.
  • Published: Jan 15, 2026
  • Updated: Jan 16, 2026
  • CVE: CVE-2026-21921
  • Severity: Medium
  • Exploit:

CVSS v3:

  • Severity: Medium
  • Score: 6.5
  • AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CWEs:

Software From Fixed in
juniper / junos - 22.4
juniper / junos 22.4 22.4.x
juniper / junos 22.4-r1 22.4-r1.x
juniper / junos 22.4-r1-s1 22.4-r1-s1.x
juniper / junos 22.4-r1-s2 22.4-r1-s2.x
juniper / junos 22.4-r2 22.4-r2.x
juniper / junos 22.4-r2-s1 22.4-r2-s1.x
juniper / junos 22.4-r2-s2 22.4-r2-s2.x
juniper / junos 22.4-r3 22.4-r3.x
juniper / junos 22.4-r3-s1 22.4-r3-s1.x
juniper / junos 22.4-r3-s2 22.4-r3-s2.x
juniper / junos 22.4-r3-s3 22.4-r3-s3.x
juniper / junos 22.4-r3-s4 22.4-r3-s4.x
juniper / junos 22.4-r3-s5 22.4-r3-s5.x
juniper / junos 22.4-r3-s6 22.4-r3-s6.x
juniper / junos 22.4-r3-s7 22.4-r3-s7.x
juniper / junos 23.2 23.2.x
juniper / junos 23.2-r1 23.2-r1.x
juniper / junos 23.2-r1-s1 23.2-r1-s1.x
juniper / junos 23.2-r1-s2 23.2-r1-s2.x
juniper / junos 23.2-r2 23.2-r2.x
juniper / junos 23.2-r2-s1 23.2-r2-s1.x
juniper / junos 23.2-r2-s2 23.2-r2-s2.x
juniper / junos 23.2-r2-s3 23.2-r2-s3.x
juniper / junos 23.2-r2-s4 23.2-r2-s4.x
juniper / junos 23.4 23.4.x
juniper / junos 23.4-r1 23.4-r1.x
juniper / junos 23.4-r1-s1 23.4-r1-s1.x
juniper / junos 23.4-r1-s2 23.4-r1-s2.x
juniper / junos_os_evolved - 22.4
juniper / junos_os_evolved 22.4 22.4.x
juniper / junos_os_evolved 22.4-r1 22.4-r1.x
juniper / junos_os_evolved 22.4-r1-s1 22.4-r1-s1.x
juniper / junos_os_evolved 22.4-r1-s2 22.4-r1-s2.x
juniper / junos_os_evolved 22.4-r2 22.4-r2.x
juniper / junos_os_evolved 22.4-r2-s1 22.4-r2-s1.x
juniper / junos_os_evolved 22.4-r2-s2 22.4-r2-s2.x
juniper / junos_os_evolved 22.4-r3 22.4-r3.x
juniper / junos_os_evolved 22.4-r3-s1 22.4-r3-s1.x
juniper / junos_os_evolved 22.4-r3-s2 22.4-r3-s2.x
juniper / junos_os_evolved 22.4-r3-s3 22.4-r3-s3.x
juniper / junos_os_evolved 22.4-r3-s4 22.4-r3-s4.x
juniper / junos_os_evolved 22.4-r3-s5 22.4-r3-s5.x
juniper / junos_os_evolved 22.4-r3-s6 22.4-r3-s6.x
juniper / junos_os_evolved 22.4-r3-s7 22.4-r3-s7.x
juniper / junos_os_evolved 23.2 23.2.x
juniper / junos_os_evolved 23.2-r1 23.2-r1.x
juniper / junos_os_evolved 23.2-r1-s1 23.2-r1-s1.x
juniper / junos_os_evolved 23.2-r1-s2 23.2-r1-s2.x
juniper / junos_os_evolved 23.2-r2 23.2-r2.x
juniper / junos_os_evolved 23.2-r2-s1 23.2-r2-s1.x
juniper / junos_os_evolved 23.2-r2-s2 23.2-r2-s2.x
juniper / junos_os_evolved 23.2-r2-s3 23.2-r2-s3.x
juniper / junos_os_evolved 23.2-r2-s4 23.2-r2-s4.x
juniper / junos_os_evolved 23.4 23.4.x
juniper / junos_os_evolved 23.4-r1 23.4-r1.x
juniper / junos_os_evolved 23.4-r1-s1 23.4-r1-s1.x
juniper / junos_os_evolved 23.4-r1-s2 23.4-r1-s2.x