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Vulnerabilities

Vulnerability · CVE-2026-21902

Juniper junos_os_evolved Incorrect Permission Assignment for Critical Resource

Published Feb 25, 2026 · catalog updated Jun 17, 2026 · Juniper

Patch now

CVE-2026-21902 is in the CISA known-exploited catalog. Confirm Juniper against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Severity
Critical9.3
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
18.38%
Remediation
Remediation guidance
Affected products
cpe juniper/junos os evolved · vendor Juniper junos_os_evolved

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe juniper/junos os evolved25.4
  • vendor Juniper junos_os_evolvedversion unspecified

How to fix CVE-2026-21902

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2026-21902 is in the CISA known-exploited catalog. Confirm Juniper against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Compare what you have installed with juniper/junos os evolved 25.4. Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

What should an analyst verify?

CWE-732: Incorrect Permission Assignment for Critical Resource. EPSS 18.38%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Feb 25, 2026 · NIST NVD

    Detected

    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 expose

  2. Mar 14, 2026 · CISA KEV

    Known exploited

    Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

  3. Jun 17, 2026 · NIST NVD

    Updated

    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 expose

Sources

  • CVE.orgVulnerability recordCVE-2026-21902

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-21902

    30-day exploitation probability 18.4%

    first.org
  • NIST NVDVulnerability recordCVE-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 s

    nvd.nist.gov
  • VulnCheck KEVConfirmed exploitationCVE-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 sh

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.