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                            CERT-Renater

                Note d'Information No. 2026/VULN232
_____________________________________________________________________

DATE                : 27/02/2026

HARDWARE PLATFORM(S): /

OPERATING SYSTEM(S): Junos OS Evolved on PTX Series versions prior
                      to 25.4R1-S1-EVO, 25.4R2-EVO*, 26.2R1-EVO*.

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https://supportportal.juniper.net/s/article/2026-02-Out-of-Cycle-Security-Bulletin-Junos-OS-Evolved-PTX-Series-A-vulnerability-allows-a-unauthenticated-network-based-attacker-to-execute-code-as-root-CVE-2026-21902
_____________________________________________________________________

2026-02 Out-of-Cycle Security Bulletin: Junos OS Evolved: PTX Series:
A vulnerability allows a unauthenticated, network-based attacker to
execute code as root (CVE-2026-21902)

Article ID
JSA107128

Created
2026-02-25

Last Updated
2026-02-25

Product Affected
This issue affects Junos OS Evolved 25.4. Affected platforms:
PTX Series.

Severity
Critical

Severity Assessment (CVSS) Score

CVSS: v3.1: 9.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)
CVSS: v4.0: 9.3 (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)


Problem

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.


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

This issue was found during internal product security testing or
research.


Solution

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

This issue is being tracked as 1914948 which is visible on the
Customer Support website.

Note: Juniper SIRT's policy is not to evaluate releases that are
beyond End of Engineering (EOE) or End of Life (EOL).


Workaround

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.

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


Severity Assessment
Information for how Juniper Networks uses CVSS can be found
at KB 16446 "Common Vulnerability Scoring System (CVSS) and
Juniper's Security Advisories."


Modification History

2026-02-25: Initial Publication

Related Information

    KB16613: Overview of the Juniper Networks SIRT Quarterly
Security Bulletin Publication Process
    KB16765: In which releases are vulnerabilities fixed?
    KB16446: Common Vulnerability Scoring System (CVSS) and
Juniper's Security Advisories
    Report a Security Vulnerability - How to Contact the
Juniper Networks Security Incident Response Team


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