CVE-2025-21601

Junos OS: SRX and EX Series, MX240, MX480, MX960, QFX5120 Series: When web management is enabled for specific services an attacker may cause a CPU spike by sending genuine packets to the device

Severity Score

8.7

*CVSS v4

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

Attend

*SSVC

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

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

*Credits: Alexander Zielke with VegaSystems GmbH & Co. KG

CVSS Scores

Attack Vector

Network

Attack Complexity

Low

Attack Requirements

None

Privileges Required

None

User Interaction

None

System

Vulnerable | Subsequent

Confidentiality

None

Integrity

None

Availability

High

Low

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Attack Vector

Network

Attack Complexity

Low

Authentication

None

Confidentiality

None

Integrity

None

Availability

Complete

* Common Vulnerability Scoring System

SSVC

Decision:Attend

Exploitation

None

Automatable

Yes

Tech. Impact

Partial

* Organization's Worst-case Scenario

Timeline

2024-12-26 CVE Reserved
2025-04-09 CVE Published
2025-04-15 CVE Updated
2025-05-11 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-573: Improper Following of Specification by Caller

CAPEC

References (1)

URL	Tag	Source

URL	Date	SRC

URL	Date	SRC

URL	Date	SRC
https://supportportal.juniper.net/JSA96452	2025-04-15

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Juniper Networks Search vendor "Juniper Networks"		Junos OS Search vendor "Juniper Networks" for product "Junos OS"				< 21.4R3-S9 Search vendor "Juniper Networks" for product "Junos OS" and version " < 21.4R3-S9"		en		Affected
Juniper Networks Search vendor "Juniper Networks"		Junos OS Search vendor "Juniper Networks" for product "Junos OS"				>= 22.2 < 22.2R3-S5 Search vendor "Juniper Networks" for product "Junos OS" and version " >= 22.2 < 22.2R3-S5"		en		Affected
Juniper Networks Search vendor "Juniper Networks"		Junos OS Search vendor "Juniper Networks" for product "Junos OS"				>= 22.4 < 22.4R3-S4 Search vendor "Juniper Networks" for product "Junos OS" and version " >= 22.4 < 22.4R3-S4"		en		Affected
Juniper Networks Search vendor "Juniper Networks"		Junos OS Search vendor "Juniper Networks" for product "Junos OS"				>= 23.2 < 23.2R2-S3 Search vendor "Juniper Networks" for product "Junos OS" and version " >= 23.2 < 23.2R2-S3"		en		Affected
Juniper Networks Search vendor "Juniper Networks"		Junos OS Search vendor "Juniper Networks" for product "Junos OS"				>= 23.4 < 23.4R2-S3 Search vendor "Juniper Networks" for product "Junos OS" and version " >= 23.4 < 23.4R2-S3"		en		Affected
Juniper Networks Search vendor "Juniper Networks"		Junos OS Search vendor "Juniper Networks" for product "Junos OS"				>= 24.2 < 24.2R1-S1 Search vendor "Juniper Networks" for product "Junos OS" and version " >= 24.2 < 24.2R1-S1"		en		Affected
Juniper Networks Search vendor "Juniper Networks"		Junos OS Search vendor "Juniper Networks" for product "Junos OS"				>= 24.2 < 24.2R2 Search vendor "Juniper Networks" for product "Junos OS" and version " >= 24.2 < 24.2R2"		en		Affected