CVE-2025-27212: UniFi Access RCE Vulnerability

CVE-2025-27212 Overview

CVE-2025-27212 is a critical command injection vulnerability affecting multiple Ubiquiti UniFi Access devices. The vulnerability stems from improper input validation that allows a malicious actor with access to the UniFi Access management network to execute arbitrary commands on affected devices. This security flaw impacts physical access control infrastructure including reader devices and intercom systems used in enterprise and residential environments.

Critical Impact

Successful exploitation enables unauthenticated attackers on the management network to achieve full system compromise through command injection, potentially allowing unauthorized physical access control manipulation, device takeover, and lateral movement within affected networks.

Affected Products

• UniFi Access Reader Pro (Version 2.14.21 and earlier)
• UniFi Access G2 Reader Pro (Version 1.10.32 and earlier)
• UniFi Access G3 Reader Pro (Version 1.10.30 and earlier)
• UniFi Access Intercom (Version 1.7.28 and earlier)
• UniFi Access G3 Intercom (Version 1.7.29 and earlier)
• UniFi Access Intercom Viewer (Version 1.3.20 and earlier)

Discovery Timeline

• 2025-08-04 - CVE-2025-27212 published to NVD
• 2025-08-05 - Last updated in NVD database

Technical Details for CVE-2025-27212

Vulnerability Analysis

This vulnerability is classified as CWE-20 (Improper Input Validation) leading to command injection. The affected UniFi Access devices fail to properly sanitize user-supplied input before passing it to system-level command execution functions. This allows an attacker positioned on the UniFi Access management network to craft malicious input that breaks out of the intended command context and executes arbitrary system commands with the privileges of the underlying service.

The attack surface requires network access to the management interface, which is typically segmented from general network traffic but may be accessible to insiders or through network misconfiguration. Once exploited, attackers gain the ability to execute commands directly on the embedded Linux-based firmware running on these physical access control devices.

Root Cause

The root cause is improper input validation in the device firmware's command handling routines. User-controlled data is incorporated into system commands without adequate sanitization or escaping, allowing shell metacharacters and command separators to be interpreted by the underlying shell. This is a classic command injection pattern where input boundaries are not enforced before concatenation with system commands.

Attack Vector

The attack vector is network-based and requires access to the UniFi Access management network. An attacker with this network position can send specially crafted requests to vulnerable endpoints on the affected devices. The attack does not require authentication, user interaction, or any special privileges, making it particularly dangerous in environments where management network segmentation is weak or compromised.

The exploitation mechanism involves injecting shell metacharacters (such as ;, |, &&, or backticks) into input fields that are subsequently processed by system shell commands. This allows arbitrary command execution with the privileges of the device firmware, potentially leading to:

• Complete device compromise
• Credential theft from device configuration
• Manipulation of physical access control policies
• Pivoting to other network resources
• Persistent backdoor installation

Detection Methods for CVE-2025-27212

Indicators of Compromise

• Unusual network traffic patterns to/from UniFi Access devices on management interfaces
• Unexpected outbound connections from access control devices to external IP addresses
• Modified configuration files or firmware on affected devices
• Suspicious process execution or shell spawning on device logs

Detection Strategies

• Monitor management network traffic for anomalous requests containing shell metacharacters or injection patterns
• Implement network intrusion detection rules to identify command injection payloads targeting UniFi Access device endpoints
• Review device logs for unexpected command execution or error messages indicating injection attempts
• Deploy endpoint detection on network segments where UniFi Access management traffic flows

Monitoring Recommendations

• Enable verbose logging on UniFi Access controller and forward logs to centralized SIEM
• Implement network segmentation monitoring to detect unauthorized access to management VLANs
• Configure alerts for firmware version mismatches indicating unpatched devices
• Monitor for unexpected device reboots or configuration changes

How to Mitigate CVE-2025-27212

Immediate Actions Required

• Identify all UniFi Access devices in your environment and verify their current firmware versions
• Isolate UniFi Access management networks from untrusted network segments immediately
• Apply firmware updates to all affected devices as specified by Ubiquiti
• Audit network access controls to ensure only authorized systems can reach management interfaces

Patch Information

Ubiquiti has released firmware updates to address this vulnerability. Organizations should update to the following versions or later:

• UniFi Access Reader Pro: Update to Version 2.15.9 or later
• UniFi Access G2 Reader Pro: Update to Version 1.11.23 or later
• UniFi Access G3 Reader Pro: Update to Version 1.11.22 or later
• UniFi Access Intercom: Update to Version 1.8.22 or later
• UniFi Access G3 Intercom: Update to Version 1.8.22 or later
• UniFi Access Intercom Viewer: Update to Version 1.4.39 or later

For complete details, refer to the UI Security Advisory Bulletin 051.

Workarounds

• Implement strict network segmentation to limit access to UniFi Access management interfaces to authorized administrative systems only
• Deploy firewall rules restricting management network access to specific trusted IP addresses
• Enable VPN requirements for remote management access to physical access control infrastructure
• Monitor and audit all traffic to management interfaces while awaiting patch deployment

# Example: Restrict management network access using iptables
# Allow only specific admin workstation IP to access UniFi Access management
iptables -A INPUT -s 192.168.10.50 -p tcp --dport 443 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP

# Alternative: VLAN-based isolation configuration
# Ensure UniFi Access devices are on dedicated management VLAN
# with strict ACLs limiting source IP ranges