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Fencer Vulns
high 7.5

CVE-2024-39530 json

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

published 2024-07-11 2 y ago modified 2026-06-17 4 mo ago also EUVD-2024-38056

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 41%
public exploits
0
none known

Summary

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.

Patch / fix

  • Juniper Networks Junos OS 21.4R3-S5, 22.1R3-S4, 22.2R3, 22.3R2-S2, 22.3R3, 22.4R2
  • juniper junos_os 21.4, 21.4r3-s5, 22.1r3-s4, 22.2r3, 22.3r2-s2, 22.3r3, 22.4r2

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.48% chance of exploitation in the next 30 days, higher than 41% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 4.0 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L
CNA 4.0 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/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:X/R:X/V:X/RE:X/U:X
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Juniper Networks Junos OS
  • juniper junos_os

Classification

Weakness
  • CWE-754 Improper Check for Unusual or Exceptional Conditions

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.