CVE-2025-21601

HIGH
Published Apr 9, 2025 Modified Aug 11, 2025 CWE-573

Description

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

CVSS v3.1 Score

7.5
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-573 CWE-573

Affected Products

Vendor Product
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos

References

Frequently Asked Questions

What is CVE-2025-21601? +
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 It has a CVSS v3.1 base score of 7.5 (HIGH).
How severe is CVE-2025-21601? +
CVE-2025-21601 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.
What products are affected by CVE-2025-21601? +
CVE-2025-21601 affects products from juniper, specifically: junos. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2025-21601? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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