HomeJuniperCVE-2026-21921

CVE-2026-21921

HIGH
7.1CVSS
Published: 2026-01-15
Updated: 2026-01-15
AI Analysis

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.

CVSS Metrics

Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:A/V:X/RE:M/U:X
Attack Vector
network
Complexity
low
Privileges
low
User Action
none
Confidentiality
undefined
Integrity
undefined
Availability
undefined
Weaknesses
CWE-416

Metadata

Primary Vendor
JUNIPER
Published
1/15/2026
Last Modified
1/15/2026
Source
NIST NVD
Note: Verify all details with official vendor sources before applying patches.

Affected Products

Juniper : Refer to Description

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