Ubiquiti UniFi OS Improper Input Validation Vulnerability
A malicious actor with access to the network could exploit an Improper Input Validation vulnerability found in UniFi OS devices to execute a Command Injection.
Severity = CVSS. Probability = EPSS (FIRST). Exploitation = public signals: KEV, EUVD, ransomware, EPSS above 10 %, no account required.
Exploitation probability EPSS · FIRST
Exploitation signals 4 / 5
- KEV catalog (CISA)23 Jun 2026
- Exploited in EUVD (ENISA)23 Jun 2026
- Used by ransomwareno
- EPSS above 10 %90.0%
- No account, over the networkyes
What to do
Fix
Apply the vendor’s fix as soon as it is available.
CISA guidance: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
Meanwhile
Take the service off the internet or restrict access to it, watch the logs and look for signs of compromise.
Manufacturers (CRA)
Exploited vulnerability in your product: early warning to ENISA within 24 h, then notification within 72 h (Article 14 of the Cyber Resilience Act). The CRA explained
Affected products
- 0 <5.1.12
- 0 <5.1.11
- 0 <5.1.10
- 0 <5.0.8
Open source packages OSV
Affected libraries according to OSV, with fixed versions.
Timeline
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Published
-
Exploitation reported (ENISA)
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Added to the KEV catalog
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CISA remediation due date
-
EPSS peak: 90.0%
References
Other exploited vulnerabilities from the same vendor
- CVE-2026-34909Ubiquiti UniFi OS Path Traversal Vulnerability8.4 · Actively exploited
- CVE-2026-34908Ubiquiti UniFi OS Improper Access Control Vulnerability9.0 · Actively exploited
- CVE-2010-5330Ubiquiti AirOS Command Injection Vulnerability7.5 · Background exploitation