What it is
CVE-2026-21902 is an unauthenticated vulnerability affecting Juniper Networks Junos OS Evolved. An Incorrect Permission Assignment for Critical Resource vulnerability in the On-Box Anomaly detection framework of...
Vulnerability report
Exploited in the wild
High confidence
Not in CISA KEV
CVE-2026-21902
Junos OS Evolved
Juniper Networks / Junos OS Evolved · affected before 25.4R1-S1-EVO, 25.4R2-EVO
- Severity
- CVSS 9.3 · Critical
- Confidence
- High
- Exploit status
- Exploited in the wild
- EPSS
- 17.7%
- First observed
- —
- Last observed
- —
Decision summary
What security teams need to know first
Direct answers before the deeper technical record.
Is it exploited?
Yes. KEV Intelligence tracks this CVE as a known exploited vulnerability. Confidence is high.
Who is affected?
Juniper Networks / Junos OS Evolved affected before 25.4r1-s1-evo, 25.4r2-evo.
What should we do?
Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
Overview
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.
Vendor
Product
Affected
Status
Juniper Networks
Junos OS Evolved
Before 25.4R1-S1-EVO, 25.4R2-EVO
Affected
Juniper Networks
Junos OS Evolved
Before 25.4R1-EVO
Unaffected
- Published
- 25 Feb 2026
- Exploitation Reported
- 19 Mar 2026
- Attack vector
- Remote
- Complexity
- Low
- Privileges
- None
- User interaction
- None
CVE References
- CVE Record CVE.org · CVE Record https://www.cve.org/CVERecord?id=CVE-2026-21902
- Vendor Advisory — supportportal.juniper.net supportportal.juniper.net · Vendor Advisory https://supportportal.juniper.net/JSA107128
- Vendor Advisory — kb.juniper.net kb.juniper.net · Vendor Advisory https://kb.juniper.net/JSA107128
Exploitation evidence
Why KEV Intelligence marks this CVE as exploited
Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.
Exploited in the wild
The Shadowserver
Independent exploitation attestation added to the KEV Intelligence record.
Known exploited vulnerability sources
Per-source evidence links for KEV attestations are available through the KEV Intelligence Pro API.
Learn about Pro API access| Source | Added |
|---|---|
| The Shadowserver First | 2026-03-19 00:00 UTC |
Detection
Operational artifacts and observed signals
Make the evidence actionable in scanner, SOC, and edge-control workflows.
Observed signals
- Request targets
- 0
- User-Agents
- 0
Raw values available in Pro and Enterprise.
Scanner coverage
No scanner integrations recorded yet.
Virtual patch status
No KEV Intelligence virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.
Learn about virtual patches →No detection artifacts or sensor request patterns are available for this CVE yet.
Check back as sensor telemetry and scanner integrations are updated.
Risk and context
Severity, weaknesses, and research context
CVSS v4.0
9.3
Critical
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
EPSS
17.7%
All CVSS Scores
CVSS v4.0
9.3
Critical
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
CVSS v3.1
9.8
Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Timeline
From disclosure to observed exploitation
-
Added to KEV Intelligence KEV Feed
High-confidence, third-party attested exploitation
-
CVE published
Vulnerability disclosed publicly
-
CVE ID reserved
Identifier reserved by the CNA
Pro API
Automate this intelligence
Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.
- Evidence confidence and provenance
- First-party sensor telemetry
- PoC and scanner references
- Affected versions and enrichment
- Automation-ready JSON delivery
GET /api/v2/pro/kevs/CVE-2026-21902
Free JSON includes basic KEV fields{
"cve_id": "CVE-2026-21902",
"confidence": "High",
"cvss_score": 9.3,
"cvss_estimated": false,
"epss_score": 0.17709,
"exploit_status": {
"exploited_in_the_wild": true,
"active_exploitation_observed": false
},
"sensor_telemetry": { "attempts": 0, "sensors": 0 }
}Early warning alerts
Get alerts on high-impact exploitation
Receive curator-selected alerts when exploitation activity warrants attention. Each alert includes the evidence and context needed to decide what requires attention now.