CVE-2026-21902 PUBLISHED

Junos OS Evolved: PTX Series: A vulnerability allows a unauthenticated, network-based attacker to execute code as root

Assigner: juniper
Reserved: 05.01.2026 Published: 25.02.2026 Updated: 26.02.2026

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.

Metrics

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:L/AU:Y/R:U/RE:M/U:Red
CVSS Score: 9.3

Product Status

Vendor Juniper Networks
Product Junos OS Evolved
Versions Default: unaffected
  • affected from 25.4 to 25.4R1-S1-EVO, 25.4R2-EVO (excl.)
  • unaffected from 0 to 25.4R1-EVO (excl.)

Exploits

Juniper SIRT is not aware of any malicious exploitation of this vulnerability.

Workarounds

To reduce the risk of exploitation of this issue, use access lists or firewall filters to limit access to only trusted networks and hosts. Please ensure such filters only permit explicitly required connections and block all others.

Also this service can be disabled by 'request pfe anomalies disable'.

Solutions

The following software releases have been updated to resolve this specific issue: 25.4R1-S1-EVO, 25.4R2-EVO, 26.2R1-EVO, and all subsequent releases. * Future Release

References

Problem Types

  • CWE-732 Incorrect Permission Assignment for Critical Resource CWE