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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.

PUBLISHED Reserved 2026-01-05 | Published 2026-01-15 | Updated 2026-01-15 | Assigner juniper




MEDIUM: 6.5CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

HIGH: 7.1CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:Y/R:A/RE:M

Problem types

CWE-416 Use After Free

Product status

Default status
unaffected

Any version before 22.4R3-S8
affected

23.2 (semver) before 23.2R2-S5
affected

23.4 (semver) before 23.4R2
affected

Default status
unaffected

Any version before 22.4R3-S8-EVO
affected

23.2 (semver) before 23.2R2-S5-EVO
affected

23.4 (semver) before 23.4R2-EVO
affected

References

supportportal.juniper.net/JSA106021 vendor-advisory

kb.juniper.net/JSA106021 vendor-advisory

cve.org (CVE-2026-21921)

nvd.nist.gov (CVE-2026-21921)

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