THREATPORT/VULNERABILITY/CVE-2026-21902
CRITICAL SEVERITY

CVE-2026-21902

Junos Os Evolved vulnerability

CVSS
9.8
EPSS
17.7%
EPSS pct
97th
Exploited
No known
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.
Affected vendor
Juniper
Affected product
Junos Os Evolved
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness type (CWE)
  • CWE-732 — Incorrect Permission Assignment for Critical Resource
Published
2026-02-25

Risk analysis

Based on its CVSS vector, this vulnerability is exploitable over the network, low attack complexity, requiring no privileges, no user interaction. Successful exploitation leads to high impact to confidentiality, high impact to integrity, high impact to availability.

Its EPSS score of 17.7% reflects a moderate probability of exploitation activity in the wild over the next 30 days, placing it above 97% of all scored CVEs.

Check your external exposure to CVE-2026-21902

  • Confirm whether Juniper Junos Os Evolved is running on any internet-facing host or subdomain.
  • Match discovered service fingerprints against the version affected by CVE-2026-21902.
  • Prioritise remediation if the asset is public, business-critical, or near authentication/payment flows.

How ThreatPort helps with CVE-2026-21902

ThreatPort's external attack surface scanner checks your internet-facing assets — agentlessly, from the outside in — for the exposed services and versions that CVE-2026-21902 affects, then prioritises the finding by real risk using CISA KEV and FIRST.org EPSS.

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