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CVE-2026-21902

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

Exploitation confirmed. First attested on 2026-03-14 by GCVE · kevintel, GCVE · shadowserver.

  • Published2026-02-25
  • WeaknessCWE-732

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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.

Timeline

dates in UTC
  1. 2026-02-2518:23CVE publishedNVD
  2. 2026-03-1411:28Listed as exploited by GCVEGCVE
  3. 2026-03-1411:28Exploitation first reportedGCVE

Versions per branch

NVD
Juniper junos os evolvedversion to verify
BranchAffectedFixed in
25.4= 25.4no fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Products declared by the CNA1 product

As juniper, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

  • Juniper Networks Junos OS Evolvedother versions: not affected

    platforms: PTX Series

    Affected
    • ≥ 25.4, < 25.4R1-S1-EVO, 25.4R2-EVOfixed in 25.4R1-S1-EVO, 25.4R2-EVOsemver

    Not affected < 25.4R1-EVO

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-02-25

Fix

Advisories and patches

Detection

read 2026-11-01 01:02 UTC
Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • NVDCVE recordread 2026-10-23
  • GCVEexploitation2026-03-14
  • CISA-ADPSSVC decisionpoc2026-03-03
  • CNACVSS 4.09.3known since 2026-10-23
  • CNACVSS 3.19.8known since 2026-10-23
  • CNAweakness (CWE)CWE-732known since 2026-10-23
  • FIRST EPSSEPSS score18.5 %read 2026-11-09
  • PoC-in-GitHubproof of concept1known since 2026-11-01
  • GitHub Advisoriesadvisory—

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 4.0 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:U/V:X/RE:M/U:Red
Published
2026-02-25
Last Modified
2026-06-17
NVD status
Analyzed
GitHub Advisory
GHSA-5w57-gjvc-whwc

Frequently asked questions

What is 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.

Is CVE-2026-21902 actively exploited?

A proof-of-concept exploit exists for CVE-2026-21902, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2026-21902?

CVE-2026-21902 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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