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
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
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
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
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
- Record
CVE-2025-21601- CVSS 4.0
- 8.7 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:Y/R:A/V:C/RE:M/U:Amber - CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-573
- Updated
- 2026-11-02
EUVDEUVD-2025-10526
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
- Record
EUVD-2025-10526- CVSS 4.0
- 8.7 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:Y/R:A/V:C/RE:M/U:Amber - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-95f3-h98w-ww8w
An Improper Following of Specification by Caller vulnerability in web management (J-Web, Captive...
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
- Record
GHSA-95f3-h98w-ww8w- CVSS 4.0
- 8.7 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:A/V:C/RE:M/U:Amber - CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-573
- Updated
- 2026-11-02
NVD
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
- Record
CVE-2025-21601- CVSS 4.0
- 8.7 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:A/V:C/RE:M/U:Amber - CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-573
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2025-21601 is a high vulnerability (CVSS 8.7) in Juniper Junos, published April 9, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.43%, the 37th percentile. No source names a fixed version.