CVE-2026-28210: FreePBX CDR Module SQL Injection Flaw

CVE-2026-28210 Overview

CVE-2026-28210 is a SQL Injection vulnerability affecting FreePBX, an open source IP PBX (Private Branch Exchange) system. The vulnerability exists in the CDR (Call Data Record) module, where improper input validation allows attackers to inject malicious SQL queries. This flaw affects FreePBX versions prior to 16.0.49 and 17.0.7, potentially enabling unauthorized database access, data manipulation, and system compromise.

Critical Impact

Authenticated attackers with high privileges can exploit this SQL injection vulnerability to extract sensitive call data records, modify database contents, or potentially achieve further system compromise through database manipulation techniques.

Affected Products

• FreePBX CDR Module versions prior to 16.0.49
• FreePBX CDR Module versions prior to 17.0.7

Discovery Timeline

• 2026-03-05 - CVE-2026-28210 published to NVD
• 2026-03-05 - Last updated in NVD database

Technical Details for CVE-2026-28210

Vulnerability Analysis

This vulnerability is classified as CWE-89 (SQL Injection), a critical class of injection flaws that occur when user-supplied data is incorporated into SQL queries without proper sanitization or parameterization. In the context of FreePBX's CDR module, the vulnerability allows attackers to manipulate SQL queries used to retrieve or manage call data records.

The attack requires network access and high privileges within the FreePBX system. Once an attacker with administrative access exploits this vulnerability, they can potentially access confidential call records, modify billing data, or manipulate audit logs stored in the database. The impact extends to confidentiality, integrity, and availability of the affected system's data.

Root Cause

The root cause of CVE-2026-28210 lies in insufficient input validation and improper construction of SQL queries within the FreePBX CDR module. User-controlled input is directly concatenated into SQL statements rather than being properly parameterized using prepared statements or equivalent safe query construction methods. This allows attackers to inject arbitrary SQL syntax that the database interprets as legitimate query commands.

Attack Vector

The attack is conducted over the network and requires the attacker to have high-level privileges within the FreePBX system. The exploitation flow involves:

1. An authenticated attacker with administrative privileges accesses the CDR module interface
2. Malicious SQL payloads are injected through vulnerable input fields or parameters
3. The application fails to sanitize the input and incorporates it directly into SQL queries
4. The database executes the attacker's injected SQL commands
5. The attacker can extract sensitive data, modify records, or potentially escalate the attack

The vulnerability does not require user interaction and can be exploited with low attack complexity once proper authentication is achieved. For detailed technical information, refer to the FreePBX Security Advisory.

Detection Methods for CVE-2026-28210

Indicators of Compromise

• Unusual or malformed SQL syntax appearing in CDR module access logs
• Unexpected database queries containing SQL injection patterns such as UNION SELECT, OR 1=1, or comment sequences (--, /*)
• Anomalous access patterns to call data records from privileged accounts
• Database error messages indicating SQL syntax errors in application logs

Detection Strategies

• Deploy Web Application Firewall (WAF) rules to detect SQL injection patterns in HTTP requests targeting FreePBX
• Implement database activity monitoring to identify suspicious query patterns including stacked queries or UNION-based injections
• Enable detailed logging on the FreePBX CDR module and analyze for injection attempt signatures
• Use intrusion detection systems (IDS) with SQL injection detection signatures

Monitoring Recommendations

• Monitor database query logs for anomalous CDR-related queries, especially those containing unexpected SQL keywords
• Implement alerting on authentication events followed by CDR module access from unusual IP addresses or times
• Review FreePBX administrative account activity for suspicious behavior patterns
• Enable audit logging for all database modifications to call data records

How to Mitigate CVE-2026-28210

Immediate Actions Required

• Update FreePBX CDR module to version 16.0.49 or later for the 16.x branch
• Update FreePBX CDR module to version 17.0.7 or later for the 17.x branch
• Review administrative account privileges and remove unnecessary high-privilege access
• Audit CDR module access logs for any indication of prior exploitation attempts

Patch Information

FreePBX has released patched versions that address this SQL injection vulnerability. Organizations should upgrade to CDR module version 16.0.49 or 17.0.7 depending on their FreePBX branch. The security advisory with complete details is available at the FreePBX Security Advisories page.

Workarounds

• Restrict network access to the FreePBX administrative interface using firewall rules or VPN requirements
• Implement strict least-privilege principles for all FreePBX administrative accounts
• Deploy a Web Application Firewall (WAF) with SQL injection protection rules in front of the FreePBX interface
• Consider temporary disabling of the CDR module if not operationally critical until patches can be applied

# Example: Restrict access to FreePBX admin interface via iptables
# Allow only trusted management network
iptables -A INPUT -p tcp --dport 80 -s 10.0.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -s 10.0.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP