Junos OS vulnerability

An Improper Authentication vulnerability in the J-Web management interface and its NETCONF session handling of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated network attacker to obtain root-level device configuration access and take over the device via a reachable J-Web HTTP or HTTPS service when web management is enabled.

Published 14 Oct 2026Updated 16 Oct 20261 sources
CVSS 9.3

What happened

An Improper Authentication vulnerability in the J-Web management interface and its NETCONF session handling of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated network attacker to obtain root-level device configuration access and take over the device via a reachable J-Web HTTP or HTTPS service when web management is enabled.

Affected versions

Junos OS: 25.2 through before 25.2R2-S2 (custom); 25.4 through before 25.4R1-S3 (custom); 26.2 through before 26.2R1-S2 (custom); 25.2 through before 25.2R2-S2-EVO (custom); 25.4 through before 25.4R1-S3-EVO (custom); 26.2 through before 26.2R1-S2-EVO (custom); 23.4X100 (custom); 25.2X100 through before 25.2X100-D35-EVO (custom); 25.4X300 through before 25.4X300-D40-EVO (custom) Fixed: See vendor advisory.

Why it matters

Review the vendor advisory and exposure of the affected product to determine operational impact.

Detection & mitigation

  • Apply vendor-provided updates or mitigations.
  • Review affected product exposure and access logs.

Public PoC references

No public PoC reference has passed the current publication threshold.