Home/CVE/An Improper Following of Specification by Caller vulnerability in web management (J-Web, Captive Portal, 802.1X, Juniper
CVE

CVE-2025-21601

An Improper Following of Specification by Caller vulnerability in web management (J-Web, Captive Portal, 802.1X, Juniper

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.

HIGH · CVSS 7.5 EPSS 0.00452
Schedule remediation
  • SSVC automatable: yes - attacks can be scripted at scale
  • CVSS base score ≥ 7.0
Sigma rules0 YARA rules0

Weakness Classification

Affected Products & Versions

2
juniper junosall versions

Scoring & Timeline

7.5
HIGH · CVSS v3.1 · sirt@juniper.net
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD09 Apr 2025 · 08:15 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
yes
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
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References & Sources

1
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
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