This vulnerability (CVE-2026-77558) is classified as CWE-125 (Out-of-bounds Read) affecting Ubiquiti Inc Dream Machines UniFi gateway devices. An unauthenticated attacker with network access can trigger an out-of-bounds read condition, leading to a Denial of Service (DoS) attack on the device. The CVSS 3.1 base score is 7.5, indicating high severity, with attack vector network, low attack complexity, no privileges required, no user interaction, and impact limited to availability (no confidentiality or integrity impact). The affected versions include all versions prior to 4.0.21, 5.1.26, and 5.1.31 as explicitly stated. There is no information on a patch or vendor advisory in the provided data.

Successful exploitation results in a Denial of Service (DoS) condition, causing the affected UniFi gateway device to become unavailable. There is no impact on confidentiality or integrity. The device's availability is disrupted, potentially affecting network operations relying on the device.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, restrict network access to trusted users and monitor device stability to detect potential exploitation attempts. No vendor patch or official fix information is provided in the input data.