CVE-2026-21902 — CRITICAL (9.8)

Vulnerability Description

An Incorrect Permission Assignment for Critical Resource vulnerability in the On-Box Anomaly detection framework of Juniper Networks Junos OS Evolved on PTX Series allows an unauthenticated, network-based attacker to execute code as root. The On-Box Anomaly detection framework should only be reachable by other internal processes over the internal routing instance, but not over an externally exposed port. With the ability to access and manipulate the service to execute code as root a remote attacker can take complete control of the device. Please note that this service is enabled by default as no specific configuration is required. This issue affects Junos OS Evolved on PTX Series: * 25.4 versions before 25.4R1-S1-EVO, 25.4R2-EVO. This issue does not affect Junos OS Evolved versions before 25.4R1-EVO. This issue does not affect Junos OS.

CVSS Score

9.8

CRITICAL

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

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality

HIGH

Integrity

HIGH

Availability

HIGH

Affected Products

Vendor	Product	Versions
Juniper	Junos Os Evolved	25.4
Juniper	Ptx10001-36Mr	-
Juniper	Ptx10002-36Qdd	-
Juniper	Ptx10003	-
Juniper	Ptx10004	-
Juniper	Ptx10008	-
Juniper	Ptx10016	-

Related Weaknesses (CWE)

CWE-732

References

https://kb.juniper.net/JSA107128MitigationVendor Advisory
https://supportportal.juniper.net/JSA107128MitigationVendor Advisory
https://github.com/watchtowrlabs/watchTowr-vs-JunosEvolved-CVE-2026-21902/blob/mProduct

FAQ

What is CVE-2026-21902?

CVE-2026-21902 is a vulnerability with a CVSS score of 9.8 (CRITICAL). An Incorrect Permission Assignment for Critical Resource vulnerability in the On-Box Anomaly detection framework of Juniper Networks Junos OS Evolved on PTX Series allows an unauthenticated, network-b...

How severe is CVE-2026-21902?

CVE-2026-21902 has been rated CRITICAL with a CVSS base score of 9.8/10. This is considered a critical vulnerability requiring immediate attention.

Is there a patch for CVE-2026-21902?

Check the references section above for vendor advisories and patch information. Affected products include: Juniper Junos Os Evolved, Juniper Ptx10001-36Mr, Juniper Ptx10002-36Qdd, Juniper Ptx10003, Juniper Ptx10004.