CVE-2026-77552 Overview
CVE-2026-77552 is a command injection vulnerability in the Ubiquiti UniFi Enterprise Audio/Video Bridge. The flaw stems from improper input validation [CWE-20] in a network-accessible interface on the device. An unauthenticated attacker with network access to the device can inject operating system commands and execute them in the context of the device firmware.
Successful exploitation grants full control over the affected bridge, exposing internal audio/video streams and providing a pivot point into enterprise networks that host UniFi infrastructure.
Critical Impact
Unauthenticated command injection over the network allows remote code execution on UniFi Enterprise Audio/Video Bridge devices, compromising confidentiality, integrity, and availability of the device and adjacent network segments.
Affected Products
- Ubiquiti UniFi Enterprise Audio/Video Bridge (see vendor advisory for firmware versions)
Discovery Timeline
- 2026-08-26 - CVE-2026-77552 published to the National Vulnerability Database
- 2026-08-26 - Last updated in NVD database
Refer to the Ubiquiti Security Advisory Bulletin 067 for vendor-supplied patch dates and fixed firmware versions.
Technical Details for CVE-2026-77552
Vulnerability Analysis
The UniFi Enterprise Audio/Video Bridge processes network-supplied input without sufficient validation before passing it to a system-level command handler. Because input is not properly sanitized or escaped, an attacker can embed shell metacharacters or additional command tokens inside a request parameter.
When the device parses the tainted input, the injected commands execute with the privileges of the receiving service. In embedded UniFi devices, that service typically runs with elevated permissions, which allows attackers to alter configuration, extract credentials, or install persistent implants on the firmware.
The attack requires no user interaction and no authentication. Any host that can reach the vulnerable service over the network can trigger the flaw.
Root Cause
The root cause is Improper Input Validation [CWE-20]. The affected code path accepts attacker-controlled data and forwards it into a command execution context without applying an allow-list, escaping shell metacharacters, or invoking safer APIs that separate command arguments from the command string.
Attack Vector
The attack vector is network-based. An attacker sends a crafted request to a service exposed by the UniFi Enterprise Audio/Video Bridge. The request contains a payload that terminates the intended argument and appends arbitrary shell commands.
Devices exposed to untrusted network segments, guest VLANs, or the internet face the highest risk. Devices placed on flat management networks alongside other UniFi infrastructure allow lateral movement after compromise.
A verified exploit example is not published in the enriched CVE data. See the Ubiquiti Security Advisory Bulletin 067 for vendor-provided technical details.
Detection Methods for CVE-2026-77552
Indicators of Compromise
- Unexpected outbound connections originating from UniFi Enterprise Audio/Video Bridge management IP addresses.
- Unusual processes, cron entries, or startup scripts on the device that do not match vendor firmware baselines.
- Configuration changes to the bridge that were not initiated by an authorized administrator.
- Anomalous log entries containing shell metacharacters such as ;, |, &&, or backticks within request parameters directed at the device.
Detection Strategies
- Inspect HTTP and API traffic to UniFi bridges for request parameters containing shell metacharacters or encoded command separators.
- Baseline expected network behavior of each bridge and alert on deviations, particularly outbound connections to non-Ubiquiti destinations.
- Correlate device syslog output with network telemetry to identify command execution events tied to inbound requests.
Monitoring Recommendations
- Forward UniFi device logs and NetFlow data to a centralized analytics platform for continuous review.
- Monitor management VLANs for scanning behavior and repeated failed or malformed requests targeting bridge services.
- Alert on firmware version drift or unexpected reboots on UniFi Enterprise Audio/Video Bridge devices.
How to Mitigate CVE-2026-77552
Immediate Actions Required
- Apply the firmware update referenced in Ubiquiti Security Advisory Bulletin 067 to every affected UniFi Enterprise Audio/Video Bridge.
- Restrict network access to bridge management interfaces so that only authorized administrator workstations can reach them.
- Audit device configurations and logs for signs of prior exploitation before and after patching.
Patch Information
Ubiquiti published fixed firmware through Security Advisory Bulletin 067. Consult the advisory for the exact firmware version that resolves CVE-2026-77552 for each hardware revision, and validate the upgrade on a representative device before broad rollout.
Workarounds
- Place UniFi Enterprise Audio/Video Bridge devices on a dedicated management VLAN with strict access control lists.
- Block inbound access to the device from untrusted networks, guest Wi-Fi, and the public internet at the perimeter firewall.
- Disable or firewall any non-essential services on the device until firmware can be applied.
# Example firewall rule restricting bridge management access to a trusted subnet
iptables -A FORWARD -s 10.10.20.0/24 -d 10.0.50.15 -p tcp --dport 443 -j ACCEPT
iptables -A FORWARD -d 10.0.50.15 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
