CVE-2024-39530: Junos OS: Attempting to access specific sensors on platforms not supporting these will lead to a chassisd crash

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-07-11 · updated 2026-06-17
Weakness: CWE-754

Description

An Improper Check for Unusual or Exceptional Conditions vulnerability in the chassis management daemon (chassisd) of Juniper Networks Junos OS allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS). If an attempt is made to access specific sensors on platforms not supporting these sensors, either via GRPC or netconf, chassisd will crash and restart leading to a restart of all FPCs and thereby a complete outage. This issue affects Junos OS: * 21.4 versions from 21.4R3 before 21.4R3-S5, * 22.1 versions from 22.1R3 before 22.1R3-S4, * 22.2 versions from 22.2R2 before 22.2R3, * 22.3 versions from 22.3R1 before 22.3R2-S2, 22.3R3, * 22.4 versions from 22.4R1 before 22.4R2. This issue does not affect Junos OS versions earlier than 21.4.

Affected products

Juniper Junos OS: 21.4-r3, 21.4-r3-s1, 21.4-r3-s2, 21.4-r3-s3, 21.4-r3-s4, 21.1-r3 (+14)

References

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