Vulnerability in Juniper Junos Os Evolved
CVE-2026-21902
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.
EPSS: 0.177 (96.8th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
Affected products
Weakness classification (CWE)
Public proof-of-concept exploits
References
- sirt@juniper.net (vendor-advisory, Mitigation, Vendor Advisory)
- sirt@juniper.net (vendor-advisory, Mitigation, Vendor Advisory)
- 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Product)
Frequently asked questions
- What is CVE-2026-21902?
- CVE-2026-21902 is a critical-severity vulnerability in Juniper Junos Os Evolved, classified under Incorrect Permission Assignment for Critical Resource. CVSS score: 9.8/10. Published 2026-02-25.
- How severe is CVE-2026-21902?
- Critical severity. CVSS v3 base score is 9.8 out of 10.
- Is CVE-2026-21902 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.