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.
- Score
- CVSS 4.0 7.1 High
- Status
- Analyzed - sirt@juniper.net
- Published
- 2026-01-15
- Last modified
- 2026-01-15
- Weaknesses
- CWE-416
Affected products
- Junos (Juniper)
- Junos Os Evolved (Juniper)
- Junos Os (Juniper Networks)
- Junos Os Evolved (Juniper Networks)
References
- https://kb.juniper.net/JSA106021
- https://supportportal.juniper.net/JSA106021