CVE-2026-77556: Ubiquiti Inc Cloud Gateways

High severity, CVSS 7.5. EPSS: 0.5% chance of exploitation in the next 30 days.

A malicious actor with access to the network could exploit an Out-of-bounds Read vulnerability found in certain UniFi gateway devices to execute a Denial of Service (DoS) attack on the device.

Affected products

• Ubiquiti Inc Cloud Gateways: before 5.1.31 (fixed in 5.1.31)
• Ubiquiti Inc Dream Machines: before 5.1.31 (fixed in 5.1.31)
• Ubiquiti Inc Dream Routers: before 5.1.31 (fixed in 5.1.31)
• Ubiquiti Inc Dream Wall: before 5.1.31 (fixed in 5.1.31)
• Ubiquiti Inc Enterprise Firewalls: before 5.1.31 (fixed in 5.1.31)
• Ubiquiti Inc Express: before 4.0.21 (fixed in 4.0.21)
• Ubiquiti Inc Express 7: before 5.1.31 (fixed in 5.1.31)
• Ubiquiti Inc UniFi Gateways: before 5.1.26 (fixed in 5.1.26)

Published 2026-09-22. Last modified 2026-09-22.