CVE-2020-5722: Grandstream Networks UCM6200 Series SQL Injection Vulnerability

CVE-2020-5722 is an unauthenticated remote SQL injection vulnerability in the Grandstream UCM6200 series. An attacker who can reach the device over the network can send a crafted HTTP request that abuses the flaw, and successful exploitation can lead to code execution as root. That combination makes the issue material for any environment where these IP-PBX / unified-communications appliances are exposed or poorly segmented.

Public detail is limited to the product family, the CWE class, and the high-level impact described by CISA. Confirm exact fixed versions, affected firmware builds, and remediation steps against the vendor advisory before acting.

How it works

The weakness is CWE-89 (SQL injection). The UCM6200 series accepts HTTP requests that ultimately influence database queries. When user-controlled input is not properly parameterized or sanitized, an attacker can alter the intended SQL statement.

Because the vulnerability is reachable without authentication, a remote attacker only needs network access to the management or service interface that processes the vulnerable request. In this class of flaw, injected SQL can often be leveraged to read or modify data, and—when the database engine or surrounding application logic permits—it can be chained to operating-system command execution. CISA notes that exploitation of this particular issue can allow code execution as root. Exact request parameters, endpoints, and payload mechanics are not provided here; treat any public proof-of-concept with caution and validate solely against the vendor’s advisory.

Am I affected? How to find it in your systems

Grandstream UCM6200 devices are typically deployed as on-premises unified-communications / IP-PBX appliances. They may sit on voice VLANs, in DMZs, or occasionally on internet-facing addresses for remote administration or SIP services.

• Inventory: Query asset-management, network-discovery, and VoIP-management systems for Grandstream UCM6200 series hardware or their management hostnames. Check DHCP, ARP, and switch CAM tables for Grandstream OUI ranges if device banners are unavailable.
• Version check: Log into each appliance’s administrative interface or use the vendor’s supported CLI/API to record the running firmware. Compare the build against the fixed versions listed in the Grandstream advisory for CVE-2020-5722; do not rely on version numbers from secondary sources.
• Exposure check: Identify whether HTTP/HTTPS management ports are reachable from untrusted networks. Review firewall rules, NAT, and any reverse-proxy or SBC configurations that forward traffic to the UCM.
• Telemetry: Look for anomalous or malformed HTTP requests hitting the device, unexpected database errors in application logs, new or unusual processes running as root, and outbound connections initiated by the appliance that do not match baseline voice/signaling traffic. Absence of such logs does not prove the device is clean.

How to remediate

Patch first. Apply the firmware update supplied by Grandstream for the UCM6200 series exactly as described in the vendor advisory. CISA’s required action is to apply updates per vendor instructions.

• Schedule a maintenance window that accounts for voice-service impact and have a tested rollback plan.
• After upgrading, re-verify the firmware version and confirm that the administrative interfaces behave as expected.
• Harden the device: disable unnecessary network services, restrict management access to dedicated jump hosts or management VLANs, enforce strong credentials and, where supported, certificate-based or multi-factor authentication, and keep the appliance off the public internet unless a documented business need exists.
• Ensure configuration backups are current and stored securely so that a clean rebuild is possible if compromise is later confirmed.

If you can't patch immediately

Implement compensating controls while you arrange the upgrade:

• Network segmentation: Place UCM6200 devices on an isolated voice or management segment; block direct access from user workstations and from the internet.
• Access control: Restrict the HTTP/HTTPS management ports to a small set of authorized administrative IP addresses via firewall or ACL. Prefer VPN or zero-trust access over direct exposure.
• Virtual patching: If a web application firewall or reverse proxy sits in front of the device, apply rules that reject obviously malformed or suspicious SQL meta-characters in HTTP parameters. Treat this only as a temporary shield; it is not a substitute for the vendor fix.
• Feature reduction: Disable any unused web or remote-administration features the vendor documentation permits.
• Heightened monitoring: Alert on new root-level processes, unexpected outbound connections, and authentication or application-error spikes. Capture full packet or HTTP logs for the management interface if storage and privacy policy allow.

These measures reduce likelihood and impact but do not eliminate the vulnerability. Plan to patch as soon as possible.

If your data may have been exposed

Actively exploited vulnerabilities of this severity can lead to full device compromise and subsequent lateral movement or data theft. Known ransomware use of CVE-2020-5722 is not documented, yet root-level access still warrants treating the appliance and any credentials or call-detail records it holds as potentially exposed. Rotate credentials that were stored on or used by the device, review call and configuration logs for unauthorized changes, and follow your incident-response process. You can also run a free exposure scan of your email addresses against known breach data sets to see whether associated accounts have appeared in prior breaches.