CVE-2026-20002: Cisco Secure FMC SQL Injection Flaw

CVE-2026-20002 Overview

CVE-2026-20002 is a SQL injection vulnerability in the web-based management interface of Cisco Secure Firewall Management Center (FMC) Software. The flaw stems from inadequate validation of user-supplied input [CWE-89]. An authenticated remote attacker can send crafted requests to an affected device and inject arbitrary SQL statements. A successful exploit grants full access to the underlying database and allows the attacker to read certain files on the host operating system. Exploitation requires valid user credentials, but no elevated privileges are needed to reach the vulnerable endpoint.

Critical Impact
Authenticated attackers can extract sensitive configuration data, credentials, and policy information from the FMC database and read files on the underlying operating system.

Affected Products

Cisco Secure Firewall Management Center (FMC) Software
Cisco Secure FMC web-based management interface
Refer to the Cisco Security Advisory for affected version details

Discovery Timeline

2026-03-04 - CVE-2026-20002 published to NVD
2026-03-05 - Last updated in NVD database

Technical Details for CVE-2026-20002

Vulnerability Analysis

The vulnerability resides in the web-based management interface of Cisco Secure FMC Software. The interface accepts user-supplied input that is incorporated into database queries without sufficient validation or parameterization. An authenticated attacker can craft requests that break out of the intended query context and inject arbitrary SQL syntax. The flaw maps to [CWE-89], Improper Neutralization of Special Elements used in an SQL Command.

Successful exploitation yields full read and write access to the FMC backend database. FMC stores firewall policies, intrusion prevention rules, access control configurations, device inventory, and operator credentials. An attacker can also leverage SQL functions to read files from the underlying operating system, expanding the scope beyond the database itself.

Root Cause

The root cause is improper input neutralization. Parameters supplied through the management interface are concatenated into SQL statements rather than bound through parameterized queries or sanitized against an allowlist. This allows attacker-controlled syntax to alter query logic.

Attack Vector

The attack vector is network-based and requires authentication. An attacker with valid credentials, including low-privilege accounts, sends crafted HTTP requests to the FMC management interface. The crafted payload manipulates back-end queries to exfiltrate database contents or invoke file-read primitives against the host. The vulnerability does not require user interaction. No public proof-of-concept code is currently associated with this CVE.

For technical specifics, refer to the Cisco Security Advisory.

Detection Methods for CVE-2026-20002

Indicators of Compromise

HTTP requests to FMC management endpoints containing SQL metacharacters such as single quotes, UNION SELECT, --, or stacked queries
Authenticated sessions issuing unusual sequences of management API requests in short timeframes
Database query logs showing unexpected SELECT operations against credential, policy, or system tables
Filesystem read attempts originating from the FMC database service account against paths outside normal application directories

Detection Strategies

Inspect FMC web server access logs for parameters containing SQL syntax tokens and encoded variants
Enable verbose database audit logging on the FMC backend and alert on queries that reference system catalogs or LOAD_FILE-style functions
Correlate authentication events with subsequent anomalous management interface activity from the same session

Monitoring Recommendations

Forward FMC syslog, web access, and audit logs to a centralized SIEM for retention and correlation
Baseline normal administrator API call patterns and alert on deviations such as bulk record retrieval
Monitor for unexpected outbound connections from the FMC appliance that may indicate data exfiltration following exploitation

How to Mitigate CVE-2026-20002

Immediate Actions Required

Apply the fixed software release identified in the Cisco Security Advisory for Cisco Secure FMC Software
Restrict access to the FMC web management interface to trusted management networks only
Audit and rotate credentials for all FMC user accounts, prioritizing accounts with broad access
Review FMC audit logs for signs of prior exploitation, including unusual queries and file reads

Patch Information

Cisco has published remediation guidance in advisory cisco-sa-fmc-sql-injection-2qH6CcJd. Administrators should consult the advisory for the list of fixed releases and upgrade paths applicable to their deployment. No official workaround that fully addresses the vulnerability has been documented; upgrading to a fixed release is the recommended path.

Workarounds

Limit management interface reachability using access control lists that permit only designated administrator workstations
Enforce multi-factor authentication on all FMC accounts to reduce the risk of credential compromise enabling exploitation
Apply least-privilege role assignments so that operator accounts cannot reach management functions beyond their duties

bash

# Example: restrict FMC management access at the network layer
# Permit only the administrator subnet to reach the FMC HTTPS interface
access-list FMC-MGMT permit tcp 10.10.20.0 0.0.0.255 host <FMC-IP> eq 443
access-list FMC-MGMT deny   tcp any host <FMC-IP> eq 443
access-list FMC-MGMT permit ip any any