EN

CVE-2025-21589

Critical
9.8
0.05.010.0
Year
2026
Published
Jan 27, 2026
Known Affected Devices
0
CVSS Score
9.8

What is CVE-2025-21589?

An Authentication Bypass Using an Alternate Path or Channel vulnerability in Juniper Networks Session Smart Router may allows a network-based attacker to bypass authentication and take administrative control of the device. This issue affects Session Smart Router:  * from 5.6.7 before 5.6.17,  * from 6.0 before 6.0.8 (affected from 6.0.8), * from 6.1 before 6.1.12-lts,  * from 6.2 before 6.2.8-lts,  * from 6.3 before 6.3.3-r2;  This issue affects Session Smart Conductor:  * from 5.6.7 before 5.6.17,  * from 6.0 before 6.0.8 (affected from 6.0.8), * from 6.1 before 6.1.12-lts,  * from 6.2 before 6.2.8-lts,  * from 6.3 before 6.3.3-r2;  This issue affects WAN Assurance Managed Routers:  * from 5.6.7 before 5.6.17,  * from 6.0 before 6.0.8 (affected from 6.0.8), * from 6.1 before 6.1.12-lts,  * from 6.2 before 6.2.8-lts,  * from 6.3 before 6.3.3-r2.

CVSS Vector Breakdown

CVSS 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
AV
Attack Vector
Network

Exploitable remotely over the network without requiring access to the local system.

AC
Attack Complexity
Low

No special conditions required. Exploit can be performed reliably and repeatedly.

PR
Privileges Required
None

No authentication required. Any anonymous user can exploit this vulnerability.

UI
User Interaction
None

No user interaction required. Exploit runs without any victim action.

S
Scope
Unchanged

Exploiting the vulnerability only affects the vulnerable component itself.

C
Confidentiality Impact
High

Complete loss of confidentiality. All data on the component may be exposed.

I
Integrity Impact
High

Complete loss of integrity. Attacker can modify any file or data on the component.

A
Availability Impact
High

Complete denial of service. The component becomes fully unavailable.

Known Affected Devices

Juniper Networks Juniper MX5 Juniper Networks Juniper MX104 Juniper Networks Juniper MX240 Juniper Networks Juniper MX480 Juniper Networks Juniper MX960 Juniper Networks Juniper MX2010 Juniper Networks Juniper MX10003 Juniper Networks Juniper PTX10003 Juniper Networks Juniper ACX1000 Juniper Networks Juniper EX2300-48P Juniper Networks Juniper EX2300-C-12T Juniper Networks Juniper EX2300-C-12P Juniper Networks Juniper EX3400-24T Juniper Networks Juniper EX3400-24P Juniper Networks Juniper EX3400-48T Juniper Networks Juniper EX3400-48P Juniper Networks Juniper EX4300-24T Juniper Networks Juniper EX4300-24P Juniper Networks Juniper EX4300-48MP Juniper Networks Juniper EX4400-24T Juniper Networks Juniper EX4400-48F Juniper Networks Juniper SRX300 Juniper Networks Juniper SRX320 Juniper Networks Juniper SRX340 Juniper Networks Juniper SRX345 Juniper Networks Juniper SRX380 Juniper Networks Juniper SRX4100 Juniper Networks Juniper SRX4200 Juniper Networks Juniper SRX4600 Juniper Networks Juniper SRX5400 Juniper Networks Juniper SRX5800 Juniper Networks Juniper QFX5100-24Q Juniper Networks Juniper QFX5110-48S Juniper Networks Juniper QFX10008 Juniper Networks Juniper QFX10016

FAQ

How severe is CVE-2025-21589?

CVE-2025-21589 has a CVSS score of 9.8/10, rated as Critical. This is the highest severity level - immediate patching is strongly recommended.

What does the CVSS score mean for CVE-2025-21589?

CVSS (Common Vulnerability Scoring System) rates vulnerability severity from 0.0 to 10.0. CVE-2025-21589 scores 9.8/10 (Critical). Scores 9.0–10.0 are Critical, 7.0–8.9 are High, 4.0–6.9 are Medium, and below 4.0 are Low.

Which devices are affected by CVE-2025-21589?

The list of devices confirmed to be affected by CVE-2025-21589 is shown in the "Affected Devices" section above. Check your firmware version against the vendor security advisory and apply the latest patch.

How do I fix or mitigate CVE-2025-21589?

Apply the latest firmware or software update from the vendor. Check the References section above for official advisories and patch notes. If no patch is available, consider disabling the affected feature or isolating the device from untrusted networks.