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NVD / CVE Program· CNA juniper

CVE-2026-21902: Junos OS Evolved: PTX Series: A vulnerability allows a unauthenticated, network-based attacker to execute code as root

Noroxi assessment

Priority: Plan (action score 43/100)

  • Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 18.4% (FIRST EPSS); higher than 97.2% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: Juniper Networks Junos OS Evolved 25.4R1-S1-EVO, 25.4R2-EVO.

Add it to your regular patch cycle. Upgrade to Juniper Networks Junos OS Evolved 25.4R1-S1-EVO, 25.4R2-EVO or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

CriticalCVSS 9.3 · v4.0—Proof of concept Fix available
Published
Feb 25, 2026
Updated
Jun 17, 2026
EPSS
18.4% · 97th percentile

Report tools

JSON

Action score

43

Plan

Add it to your regular patch cycle.

CVSS
37 / 40 · 9.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
6 / 30 · 18.4%

CISA SSVC decision

Exploitation
proof of concept
Automatable
yes
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · juniper
9.8
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • Proof of concept exists, no weaponized module
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-21902

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
juniperjunos os evolved
juniperptx10001-36mr
juniperptx10002-36qdd
juniperptx10003
juniperptx10004
juniperptx10008
juniperptx10016

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • juniper junos os evolved25.4

Versions reported by the vendor

Affected version ranges reported by the assigning authority (juniper). Independent of NVD's CPE analysis and usually ahead of it.

  • Juniper Networks Junos OS Evolved

    • 25.4 and later · before 25.4R1-S1-EVO, 25.4R2-EVOaffected · semver
    • before 25.4R1-EVOnot affected · semver

Same product

juniper: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-101990Junos OS and Junos OS Evolved: A BGP peer causes an rpd crash when flow-spec routes are re-advertised
    37Monitor
  • CVE-2026-101986Junos OS and Junos OS Evolved: J-Web permits pre-authentication CGI execution
    37Monitor
  • CVE-2023-28983Junos OS Evolved: Shell Injection vulnerability in the gNOI server
    35Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2025-60006Oct 9, 2025 · Junos OS Evolved: OS command injection vulnerabilities fixed
    19Monitor
  • ← EarlierCVE-2026-21911Jan 15, 2026 · Junos OS Evolved: Flapping management interface causes MAC learning on label-switched interfaces to stop
    28Monitor
  • Later →CVE-2025-59969Apr 9, 2026 · Junos OS Evolved: QFX5000 Series and PTX Series: An attacker sending crafted multicast packets will cause evo-aftmand / evo-pfemand to crash and restart
    28Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Juniper Networks Junos OS Evolved25.4R1-S1-EVO, 25.4R2-EVOVendor (CNA)

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

  • Proof-of-concept repository on GitHub ×1

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Proof-of-concept repository on GitHubstars:42026-02-28

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. First PoC+2 d
  3. TodayOct 31, 2026+248 d

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
X

Weakness class (CWE)

CWE-732 · Incorrect Permission Assignment for Critical Resource

CVSS 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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records