Detect Ubiquiti UniFi OS Improper Input Validation Vulnerability (CVE-2026-34910) in Microsoft Sentinel
Detects exploitation attempts targeting CVE-2026-34910, an improper input validation vulnerability in Ubiquiti UniFi OS. This vulnerability is listed on CISA's Known Exploited Vulnerabilities catalog and allows attackers to send malformed or unexpected input to UniFi OS network management interfaces, potentially leading to unauthorized access, command execution, or device compromise. UniFi OS powers a wide range of Ubiquiti network devices including Dream Machines, Cloud Keys, and network switches used in enterprise and SMB environments.
MITRE ATT&CK
KQL Detection Query
let UniFiPorts = dynamic([443, 8443, 8080, 80]);
let SuspiciousPatterns = dynamic(["../", "..%2f", "..%2F", "%00", "<script", "';--", "union select", "exec(", "eval(", "cmd=", "command=", "ping -c", "wget ", "curl "]);
union DeviceNetworkEvents, CommonSecurityLog
| where TimeGenerated > ago(24h)
| where (DeviceName contains "unifi" or DeviceName contains "ubiquiti" or DeviceVendor contains "Ubiquiti" or DestinationPort in (UniFiPorts))
| where RequestURL has_any (SuspiciousPatterns) or RequestContext has_any (SuspiciousPatterns) or AdditionalExtensions has_any (SuspiciousPatterns)
| project TimeGenerated, SourceIP, DestinationIP, DestinationPort, RequestURL, RequestMethod, ResponseCode, DeviceName, DeviceVendor
| summarize AttemptCount=count(), DistinctURLs=dcount(RequestURL), SampleURLs=make_set(RequestURL, 5) by SourceIP, DestinationIP, bin(TimeGenerated, 5m)
| where AttemptCount > 3
| order by AttemptCount descDetects suspicious HTTP/HTTPS requests to Ubiquiti UniFi OS management interfaces containing input validation bypass patterns such as path traversal sequences, injection strings, or malformed parameters indicative of CVE-2026-34910 exploitation.
Data Sources
Required Tables
False Positives & Tuning
- Legitimate administrative scripts that probe UniFi device APIs with complex query parameters
- Vulnerability scanners (Nessus, Qualys, Tenable) performing authorized assessments against UniFi infrastructure
- Penetration testing activities targeting UniFi devices under authorized engagements
- URL-encoded characters in legitimate administrative traffic from UniFi mobile apps or controllers
Other platforms for CVE-2026-34910
Testing Methodology
Validate this detection against 3 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1CVE-2026-34910 Path Traversal Probe Against UniFi OS API
Expected signal: HTTP requests with path traversal sequences ('../', '%2f') in URL paths to port 443 should appear in web proxy logs, firewall logs, and IDS/IPS alerts
- Test 2CVE-2026-34910 Command Injection Parameter Fuzzing
Expected signal: HTTP GET requests containing command injection strings (cmd=, command=, exec(), eval()) in query parameters to port 8443 visible in network logs
- Test 3CVE-2026-34910 Authenticated API Manipulation with Malformed Input
Expected signal: POST/PUT requests with SQL injection and command injection strings in JSON body fields to UniFi OS API endpoints; authentication attempts with malformed username fields
References (4)
- https://community.ui.com/releases/Security-Advisory-Bulletin-064-064/84811c09-4cf4-42ab-bd61-cc994445963b
- https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
- https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk
- https://nvd.nist.gov/vuln/detail/CVE-2026-34910
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