What it is
CVE-2023-36851 is an unauthenticated vulnerability affecting Juniper Networks Junos OS. A Missing Authentication for Critical Function vulnerability in Juniper Networks Junos OS on SRX Series allows an...
Vulnerability report
Exploited in the wild
Confirmed confidence
In CISA KEV
CVE-2023-36851
Junos OS
Juniper Networks / Junos OS · affected before 21.2R3-S8
- Severity
- CVSS 5.3 · Medium
- Confidence
- Confirmed
- Exploit status
- Exploited in the wild
- EPSS
- 1.1%
- 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 confirmed.
Who is affected?
Juniper Networks / Junos OS affected before 21.2r3-s8.
What should we do?
Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
Overview
Junos OS
A Missing Authentication for Critical Function vulnerability in Juniper Networks Junos OS on SRX Series allows an unauthenticated, network-based attacker to cause limited impact to the file system integrity.
With a specific request to
webauth_operation.php
that doesn't require authentication, an attacker is able to upload and download arbitrary files via J-Web, leading to a loss of
integrity or confidentiality, which may allow chaining to other vulnerabilities.
This issue affects Juniper Networks Junos OS on SRX Series:
*
21.2 versions prior to 21.2R3-S8; * 21.4
versions prior to
21.4R3-S6; * 22.1
versions prior to
22.1R3-S5; * 22.2
versions prior to
22.2R3-S3; * 22.3
versions prior to
22.3R3-S2; * 22.4 versions prior to 22,4R2-S2, 22.4R3; * 23.2 versions prior to
23.2R1-S2, 23.2R2.
Vendor
Product
Affected
Status
Juniper Networks
Junos OS
Before 21.2R3-S8
Affected
Juniper Networks
Junos OS
Before 21.4R3-S6
Affected
Juniper Networks
Junos OS
Before 22.1R3-S5
Affected
Juniper Networks
Junos OS
Before 22.2R3-S3
Affected
Juniper Networks
Junos OS
Before 22.3R3-S2
Affected
Juniper Networks
Junos OS
Before 22.4R2-S2, 22.4R3
Affected
Juniper Networks
Junos OS
Before 23.2R1-S2, 23.2R2
Affected
- Published
- 26 Sep 2023
- Exploitation Reported
- 13 Nov 2023
- Attack vector
- Remote
- Complexity
- Low
- Privileges
- None
- User interaction
- None
Tags
edge
php
nessus_scanner
cisa
CVE References
- CVE Record CVE.org · CVE Record https://www.cve.org/CVERecord?id=CVE-2023-36851
- Vendor Advisory — supportportal.juniper.net supportportal.juniper.net · Vendor Advisory https://supportportal.juniper.net/JSA72300
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
CISA
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 |
|---|---|
| CISA First | 2023-11-13 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
Nessus template detected 02 Jun 2025.
View Nessus template (opens in new tab)Virtual patch status
No KEV Intelligence virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.
Learn about virtual patches →Scanner Artifacts
Scanner and exploit-framework references linked to this CVE.
| Scanner | Reference | Detected |
|---|---|---|
| Nessus | https://www.tenable.com/plugins/nessus/180190 | 02 Jun 2025 |
Risk and context
Severity, weaknesses, and research context
CVSS v3.1
5.3
Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
EPSS
1.1%
Timeline
From disclosure to observed exploitation
-
Nessus plugin available
Scanner coverage available
-
Added to CISA KEV
Listed in the CISA Known Exploited Vulnerabilities catalog
-
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-2023-36851
Free JSON includes basic KEV fields{
"cve_id": "CVE-2023-36851",
"confidence": "Confirmed",
"cvss_score": 5.3,
"cvss_estimated": false,
"epss_score": 0.01091,
"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.