CVE-2026-20003 Overview
A SQL injection vulnerability exists in the REST API of Cisco Secure Firewall Management Center (FMC) Software that could allow an authenticated, remote attacker to conduct SQL injection attacks on affected systems. The vulnerability stems from inadequate validation of user-supplied input in the REST API endpoints, enabling attackers with valid credentials to send specially crafted requests that manipulate database queries.
Critical Impact
Successful exploitation allows attackers to obtain unauthorized read access to the database and read certain files on the underlying operating system, potentially exposing sensitive configuration data, credentials, and network security policies.
Affected Products
- Cisco Secure Firewall Management Center (FMC) Software
- Cisco FMC REST API endpoints
Discovery Timeline
- 2026-03-04 - CVE CVE-2026-20003 published to NVD
- 2026-03-05 - Last updated in NVD database
Technical Details for CVE-2026-20003
Vulnerability Analysis
This vulnerability is classified as CWE-89: Improper Neutralization of Special Elements used in an SQL Command (SQL Injection). The flaw resides in the REST API component of Cisco Secure FMC Software, where user-supplied input is not properly sanitized before being incorporated into SQL queries. While the vulnerability requires authentication, it can be exploited by users with various administrative roles including Administrator, Security approver, Intrusion admin, Access admin, and Network admin.
The attack requires network access to the FMC management interface and valid credentials with elevated privileges. Upon successful exploitation, attackers gain read access to the underlying database, which may contain sensitive security configurations, policy definitions, and potentially credentials for other network devices managed by the FMC.
Root Cause
The root cause is inadequate validation of user-supplied input within the REST API request handling logic. When processing API requests, the affected code fails to properly sanitize or parameterize input values before including them in database queries. This allows an attacker to inject malicious SQL statements that are then executed by the database engine with the privileges of the application.
Attack Vector
The attack is conducted remotely over the network against the FMC REST API. An attacker must first obtain valid credentials for an account with one of the privileged roles (Administrator, Security approver, Intrusion admin, Access admin, or Network admin). Once authenticated, the attacker crafts malicious API requests containing SQL injection payloads in vulnerable parameters.
The vulnerability mechanism involves sending crafted HTTP requests to REST API endpoints where input parameters are improperly handled. For technical details on the specific attack methodology, refer to the Cisco Security Advisory.
Detection Methods for CVE-2026-20003
Indicators of Compromise
- Unusual or malformed REST API requests containing SQL syntax characters such as single quotes, semicolons, UNION, SELECT, or comment sequences
- Unexpected database query patterns or errors in FMC application logs
- Anomalous file access attempts on the underlying operating system from the FMC application context
- Authentication events from privileged accounts followed by suspicious API activity
Detection Strategies
- Deploy web application firewall (WAF) rules to detect SQL injection patterns in API traffic to the FMC management interface
- Enable comprehensive logging on the FMC REST API and monitor for requests containing SQL injection signatures
- Implement anomaly detection for database queries originating from the FMC application
- Monitor authentication logs for privileged account access, especially from unexpected source IPs
Monitoring Recommendations
- Enable detailed audit logging for all REST API access on Cisco FMC
- Configure SIEM correlation rules to alert on SQL injection attempt patterns targeting FMC endpoints
- Monitor database query logs for unusual SELECT operations or file read operations
- Review privileged account activity regularly and implement behavioral analytics for administrator accounts
How to Mitigate CVE-2026-20003
Immediate Actions Required
- Review the Cisco Security Advisory for the latest patch information and apply available security updates
- Audit all accounts with Administrator, Security approver, Intrusion admin, Access admin, and Network admin roles
- Restrict network access to the FMC management interface to trusted administrative networks only
- Monitor API access logs for any signs of exploitation attempts
Patch Information
Cisco has released security updates to address this vulnerability. Organizations should consult the official Cisco Security Advisory for specific version information and upgrade guidance. Apply patches during the next available maintenance window following your organization's change management procedures.
Workarounds
- Implement strict network segmentation to limit access to the FMC management interface from authorized management workstations only
- Deploy a web application firewall (WAF) or API gateway with SQL injection detection rules in front of the FMC management interface
- Enforce multi-factor authentication for all privileged FMC accounts to reduce the risk of credential compromise
- Implement the principle of least privilege by reviewing and reducing the number of accounts with elevated roles
# Example: Restrict FMC management access via firewall rules
# Allow management access only from trusted admin subnet
iptables -A INPUT -p tcp --dport 443 -s 10.10.10.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
