CVE-2025-21601

Summary

An Improper Following of Specification by Caller vulnerability in web management (J-Web, Captive Portal, 802.1X, Juniper Secure Connect (JSC) of Juniper Networks Junos OS on SRX Series, EX Series, MX240, MX480, MX960, QFX5120 Series, allows an unauthenticated, network-based attacker, sending genuine traffic targeted to the device to cause the CPU to climb until the device becomes unresponsive.

Continuous receipt of these packets will create a sustained Denial of Service (DoS) condition.

This issue affects Junos OS: 

  • All versions before 21.4R3-S9,
  • from 22.2 before 22.2R3-S5,
  • from 22.4 before 22.4R3-S4,
  • from 23.2 before 23.2R2-S3,
  • from 23.4 before 23.4R2-S3,
  • from 24.2 before 24.2R1-S1, 24.2R2.

An indicator of compromise is to review the CPU % of the httpd process in the CLI: e.g.   show system processes extensive | match httpd  PID nobody       52   0   20M    191M select   2   0:01   80.00% httpd{httpd} <<<<< the percentage of httpd usage if high may be an indicator

Affected Software

VendorProductVersion RangeStatus
Juniper NetworksJunos OS0 < 21.4R3-S9affected
Juniper NetworksJunos OS22.2 < 22.2R3-S5affected
Juniper NetworksJunos OS22.4 < 22.4R3-S4affected
Juniper NetworksJunos OS23.2 < 23.2R2-S3affected
Juniper NetworksJunos OS23.4 < 23.4R2-S3affected
Juniper NetworksJunos OS24.2 < 24.2R1-S1, 24.2R2affected

Weaknesses

  • 573 - Improper Following of Specification by Caller

Workarounds

There are no known workarounds for this issue.

To reduce the risk of exploitation use authentication when using web management services.

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: yes
    • Technical Impact: partial

References