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CVE PROGRAM SOURCE RECORD7.1 High

CVE-2026-21921

Junos OS and Junos OS Evolved: When telemetry collectors are frequently subscribing and unsubscribing to sensors chassisd or rpd will crash

Description

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.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Juniper Networks Junos OS

Default version status: unaffected

  • 0 to < 22.4R3-S8affected
  • 23.2 to < 23.2R2-S5affected
  • 23.4 to < 23.4R2affected

Juniper Networks Junos OS Evolved

Default version status: unaffected

  • 0 to < 22.4R3-S8-EVOaffected
  • 23.2 to < 23.2R2-S5-EVOaffected
  • 23.4 to < 23.4R2-EVOaffected

References