CVE-2026-20344: Cisco Secure FMC SQL Injection Vulnerability

CVE-2026-20344 Overview

CVE-2026-20344 is a SQL injection vulnerability in the web-based management interface of Cisco Secure Firewall Management Center (FMC) Software. An authenticated remote attacker can send crafted HTTP requests to extract database contents, hijack administrator sessions, and execute actions with administrative privileges. Exploitation requires a valid account with the role of Security Approver, Access Admin, or Network Admin. The flaw is tracked under CWE-89 and stems from insufficient validation of user-supplied input.

Critical Impact
Successful exploitation allows attackers to read arbitrary database contents, steal authenticated Administrator session credentials, and take administrative actions on the affected FMC device.

Affected Products

Cisco Secure Firewall Management Center (FMC) Software
Web-based management interface component
Refer to the Cisco Security Advisory for fixed release versions

Discovery Timeline

2026-09-16 - CVE-2026-20344 published to NVD
2026-09-16 - Last updated in NVD database

Technical Details for CVE-2026-20344

Vulnerability Analysis

The vulnerability resides in the web-based management interface of Cisco Secure FMC Software. User-supplied input reaches back-end SQL query construction without sufficient validation or parameterization. An authenticated attacker can inject SQL syntax through crafted HTTP request parameters processed by the interface.

Exploitation requires prior authentication with one of three elevated roles: Security Approver, Access Admin, or Network Admin. Once authenticated, the attacker submits crafted requests that alter query semantics. The application executes the modified queries against the FMC database with the privileges of the web application.

A successful attack yields three distinct outcomes. First, the attacker reads arbitrary rows from the database, including configuration and credential material. Second, the attacker retrieves active session credentials belonging to an authenticated Administrator. Third, the attacker replays those credentials to perform any action available to an Administrator on the FMC. This turns a mid-privilege account into full administrative control of the firewall management plane.

Root Cause

The root cause is improper neutralization of special elements used in an SQL command [CWE-89]. The affected endpoints concatenate attacker-controlled parameters into SQL statements instead of using parameterized queries or strict input allow-lists.

Attack Vector

The attack vector is network-based against the FMC web management interface. The attacker authenticates with a Security Approver, Access Admin, or Network Admin account and sends a crafted HTTP request. The request contains SQL metacharacters in a parameter that the application forwards into a database query. No user interaction is required beyond the attacker's own authenticated session.

No verified public exploit code is available. See the Cisco Security Advisory for technical details.

Detection Methods for CVE-2026-20344

Indicators of Compromise

HTTP requests to FMC management endpoints containing SQL metacharacters such as single quotes, UNION SELECT, --, or hex-encoded payloads in parameter values.
Unexpected Administrator session activity originating from accounts that normally hold only Security Approver, Access Admin, or Network Admin roles.
Database error responses or anomalous response sizes returned from FMC web management endpoints.

Detection Strategies

Enable and forward FMC audit logs and web-server access logs to a centralized analytics platform for pattern matching against SQL injection signatures.
Correlate authentication events with subsequent administrative configuration changes to detect privilege escalation from mid-tier roles.
Baseline normal HTTP parameter values submitted by each administrative role and alert on high-entropy or syntactically anomalous submissions.

Monitoring Recommendations

Monitor FMC administrator account creation, role changes, and policy modifications outside change-management windows.
Alert on repeated 500-class HTTP responses from FMC management URLs that may indicate injection probing.
Track session token reuse across source IPs to identify hijacked Administrator sessions.

How to Mitigate CVE-2026-20344

Immediate Actions Required

Apply the fixed Cisco Secure FMC Software release listed in the Cisco Security Advisory.
Restrict access to the FMC web management interface to a dedicated management network and trusted administrator workstations only.
Audit accounts holding Security Approver, Access Admin, and Network Admin roles, and remove or rotate credentials for any account no longer required.
Invalidate active FMC administrator sessions and rotate administrator credentials after patching.

Patch Information

Cisco has published fixed software releases through the Cisco Security Advisory cisco-sa-fmc-mulivulns-4PsnFwvx. Administrators should consult the advisory for the specific fixed versions applicable to their deployment and follow Cisco's upgrade procedure. No workaround is available from Cisco for this vulnerability.

Workarounds

No vendor-supplied workaround exists. Upgrading to a fixed release is the required remediation.
As a compensating control, enforce strict network segmentation and access control lists that limit reachability of the FMC management interface.
Enforce multi-factor authentication on all FMC administrative accounts to reduce the risk of credential compromise leading to exploitation.

bash

# Configuration example: restrict management interface access via ACL
# Replace <mgmt_admin_subnet> and <fmc_mgmt_ip> with environment values
access-list FMC_MGMT_ACL permit tcp <mgmt_admin_subnet> host <fmc_mgmt_ip> eq 443
access-list FMC_MGMT_ACL deny   tcp any host <fmc_mgmt_ip> eq 443
access-list FMC_MGMT_ACL deny   tcp any host <fmc_mgmt_ip> eq 80