Junos OS (SRX firewalls)
CVE-2024-39530: Attempting to access specific sensors on platforms not supporting these will lead to a chassisd crash
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).
Published
Automatic summary from the vendor's CVE record. We haven't written a full analysis of this vulnerability yet.
Affected and fixed versions
| Product / branch | Fixed in |
|---|---|
| Junos OS 21.4R3 | 21.4R3-S5 or later |
| Junos OS 22.1R3 | 22.1R3-S4 or later |
| Junos OS 22.2R2 | 22.2R3 or later |
| Junos OS 22.3R1 | 22.3R2-S2, 22.3R3 or later |
| Junos OS 22.4R1 | 22.4R2 or later |
| Junos OS 0 | Not affected |
Always confirm against the vendor advisory, which lists every fixed hotfix.
What it is
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.
Am I affected?
For this issue to be exploited over GRPC it needs to be configured as follows:
[ system services extension-service request-response grpc ]
Workarounds
There are no known workarounds for this issue.
Exploitation
Juniper SIRT is not aware of any malicious exploitation of this vulnerability.
Sources
KEV status, EPSS score and vendor data refreshed automatically, last on 13 Oct 2026.