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

HIGH

7.5

CVSS Score

Published: April 9, 2025 at 07:51 PM UTC

Updated: June 17, 2026 at 08:43 AM UTC

1 product affected across 1 vendorJunos

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Severity

HIGH7.5

Exploit prediction

EPSS 0.4%

SSVC

No known exploit

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

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Junos · Juniper Networks

95%

v ≤ 21.4v < 21.4R3-S922.2 ≤ v < 22.2R3-S522.4 ≤ v < 22.4R3-S423.2 ≤ v < 23.2R2-S323.4 ≤ v < 23.4R2-S324.2 ≤ v < 24.2R1-S1, 24.2R221.4 r1 21.4 r1-s1 21.4 r1-s2 21.4 r2 21.4 r2-s1 21.4 r2-s2 21.4 r3 21.4 r3-s1 21.4 r3-s2 21.4 r3-s3 21.4 r3-s4 21.4 r3-s5 21.4 r3-s6 21.4 r3-s7 21.4 r3-s8 22.2 22.2 r1 22.2 r1-s1 22.2 r1-s2 22.2 r2 22.2 r2-s1 22.2 r2-s2 22.2 r3 22.2 r3-s1 22.2 r3-s2 22.2 r3-s3 22.2 r3-s4 22.4 22.4 r1 22.4 r1-s1 22.4 r1-s2 22.4 r2 22.4 r2-s1 22.4 r2-s2 22.4 r3 22.4 r3-s1 22.4 r3-s2 22.4 r3-s3 23.2 23.2 r1 23.2 r1-s1 23.2 r1-s2 23.2 r2 23.2 r2-s1 23.2 r2-s2 23.4 23.4 r1 23.4 r1-s1 23.4 r1-s2 23.4 r2 23.4 r2-s1 23.4 r2-s2 24.2 24.2 r1

Affected range stops below 21.4R3-S9, so it looks safe — our inference, not a vendor statement

Affected range stops below 22.2R3-S5, so it looks safe — our inference, not a vendor statement

Affected range stops below 22.4R3-S4, so it looks safe — our inference, not a vendor statement

Affected range stops below 23.2R2-S3, so it looks safe — our inference, not a vendor statement

Affected range stops below 23.4R2-S3, so it looks safe — our inference, not a vendor statement

Affected range stops below 24.2R1-S1, 24.2R2, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

https://supportportal.juniper.net/JSA96452

References (1)

Vendor Advisory

Source: [email protected]

https://supportportal.juniper.net/JSA96452

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHjuniper

Attack Vector: NETWORK
Complexity: LOW
Privileges: NONE
User Interaction: NONE
Scope: UNCHANGED
Confidentiality: NONE
Integrity: NONE
Availability: HIGH

Vector?

Quick Info

StatusANALYZED

CWE

CWE-573

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