Unrated severityNVD Advisory· Published Jan 15, 2026· Updated Jan 15, 2026
Junos OS and Junos OS Evolved: When telemetry collectors are frequently subscribing and unsubscribing to sensors chassisd or rpd will crash
CVE-2026-21921
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
1- Range: 0
Patches
0No patches discovered yet.
Vulnerability mechanics
AI mechanics synthesis has not run for this CVE yet.
References
2- kb.juniper.net/JSA106021mitrevendor-advisory
- supportportal.juniper.net/JSA106021mitrevendor-advisory
News mentions
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