CVE-2025-53681: Fortinet FortiMail SQLi Vulnerability

CVE-2025-53681 Overview

CVE-2025-53681 is a SQL injection vulnerability [CWE-89] affecting Fortinet FortiMail. The flaw stems from improper neutralization of special elements in SQL commands processed through the FortiMail web management interface. An authenticated attacker with high privileges can execute unauthorized code or commands by sending specifically crafted HTTP or HTTPS requests.

The vulnerability affects FortiMail 7.6.0 through 7.6.3, 7.4.0 through 7.4.5, and 7.2.0 through 7.2.8. Fortinet published the security advisory FG-IR-26-132 documenting the issue and providing remediation guidance.

Critical Impact
Authenticated privileged attackers can execute arbitrary code or commands against affected FortiMail instances, compromising email security gateway integrity, confidentiality, and availability.

Affected Products

Fortinet FortiMail 7.6.0 through 7.6.3
Fortinet FortiMail 7.4.0 through 7.4.5
Fortinet FortiMail 7.2.0 through 7.2.8

Discovery Timeline

2026-05-12 - CVE-2025-53681 published to NVD
2026-05-15 - Last updated in NVD database

Technical Details for CVE-2025-53681

Vulnerability Analysis

The vulnerability resides in FortiMail's handling of HTTP and HTTPS requests sent to the administrative interface. Input parameters are passed into SQL queries without proper sanitization or parameterization. An attacker authenticated with high privileges can inject malicious SQL syntax through specially crafted request parameters.

Successful exploitation allows the attacker to escape the intended query context. The injection can be leveraged beyond data manipulation to achieve unauthorized code or command execution on the appliance. This elevates the impact from data exposure to full host compromise of the email security gateway.

The attack vector is network-based and requires no user interaction. The high privilege prerequisite limits exploitation to attackers with valid administrative credentials, compromised admin sessions, or insiders.

Root Cause

The root cause is improper neutralization of special elements used in SQL commands. Application logic concatenates attacker-controllable input into SQL statements without using prepared statements or strict input validation. Special characters that should terminate or alter query structure are not escaped before execution.

Attack Vector

Exploitation requires the attacker to authenticate to the FortiMail administrative interface with high privileges. The attacker then submits HTTP or HTTPS requests containing crafted SQL payloads in vulnerable parameters. The backend processes the malicious input, executes the injected SQL, and enables follow-on command or code execution paths described in the Fortinet advisory.

No verified public proof-of-concept exploit is currently available. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog. EPSS data shows a low probability of near-term exploitation.

Detection Methods for CVE-2025-53681

Indicators of Compromise

Unexpected administrative HTTP or HTTPS requests containing SQL metacharacters such as single quotes, UNION, SELECT, or comment sequences in parameter values.
New or modified administrative accounts on FortiMail appliances without corresponding change tickets.
Unusual outbound connections or process activity originating from the FortiMail management plane.
Anomalous database query patterns or errors recorded in FortiMail system logs.

Detection Strategies

Inspect FortiMail web access logs for parameter values containing SQL syntax or encoded payloads targeting administrative endpoints.
Correlate authenticated administrator sessions with subsequent configuration changes, account creation, or command execution events.
Deploy web application firewall rules in front of the FortiMail management interface to flag SQL injection signatures.

Monitoring Recommendations

Forward FortiMail audit and HTTPD logs to a centralized SIEM or data lake for long-term retention and correlation.
Alert on administrative logins from unexpected source IPs or outside maintenance windows.
Monitor for failed and successful privilege-level authentication anomalies against the FortiMail management interface.

How to Mitigate CVE-2025-53681

Immediate Actions Required

Upgrade FortiMail to a fixed release as specified in the Fortinet Security Advisory FG-IR-26-132.
Restrict access to the FortiMail administrative interface to trusted management networks only.
Rotate administrative credentials and review all privileged accounts for unauthorized additions or changes.
Audit recent administrative activity for signs of exploitation prior to patching.

Patch Information

Fortinet documents fixed versions in advisory FG-IR-26-132. Administrators should consult the Fortinet Security Advisory for the specific upgrade paths corresponding to FortiMail 7.2.x, 7.4.x, and 7.6.x deployments.

Workarounds

Limit administrative interface exposure using firewall ACLs and trust-host configuration on FortiMail.
Enforce multi-factor authentication for all administrative accounts to reduce the risk of credential-based exploitation.
Apply principle of least privilege to FortiMail administrator roles, minimizing the number of accounts with high privilege levels.

bash

# Restrict administrative access to a trusted management subnet
config system admin
  edit "admin"
    set trusthost1 10.0.0.0 255.255.255.0
  next
end