CVE-2026-34908: Ubiquiti UniFi OS Improper Access Control Vulnerability
What it is
Ubiquiti UniFi OS contains an improper access control vulnerability which could allow a malicious actor with access to the network to make unauthorized changes to the system.
What to do
Treat this as urgent. Identify every affected system, starting with anything internet-facing, and apply the vendor fix or mitigation within days. If you cannot patch quickly, isolate or disable the affected service and watch for signs of compromise.
- Priority
- Act now: Patch or mitigate internet-facing systems within days.
- Severity (CVSS)
- 10 critical (vendor’s score; NVD analysis pending)
- CISA assessment (SSVC)
- actively exploited; attackers can automate it at scale; total control of the affected system
- Exploit probability (EPSS, 30 days)
- 15%, higher than 96% of all CVEs
- Added to CISA KEV
- 23 June 2026
- CISA fix-by date
- 26 June 2026 (US federal agencies; a sensible deadline for everyone)
- Ransomware use
- Not known
References
Sources: CISA Known Exploited Vulnerabilities · FIRST Exploit Prediction Scoring System (EPSS) · NIST National Vulnerability Database · CISA Vulnrichment (SSVC), via the CVE Program. This product uses data from the NVD API but is not endorsed or certified by the NVD. Summaries are machine-written from CISA’s description; treat the vendor’s advisory as the authority for fixes.