External risk intelligence

Fastadmin SQL Injection Vulnerability Allows Arbitrary Code Execution

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2026-51775

FastAdmin is a web-based administrative framework commonly deployed as a web application. As a backend controller component, it is typically accessible via web interfaces, making it a likely target for internet-based exposure when deployed as part of a web application stack.

SQL Injection

Halo Surface Signal: 4 out of 5 — likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A critical SQL injection vulnerability has been identified in FastAdmin, a web-based administrative framework. This flaw could allow unauthorized code execution by unauthenticated attackers through a specific component in the application's backend controller. The main concern is confirming relevance and exposure to any deployed instances.

Unauthenticated code execution via web applications.
Matters due to potential unauthorized system control.
Confirm relevance and identify any exposure.

Attack Path

How an attacker could exploit the issue

An unauthenticated attacker can exploit this vulnerability by sending a specially crafted request to the application's backend. This request targets a component that handles common backend operations, allowing the attacker to inject malicious SQL commands. Successful exploitation could lead to the execution of arbitrary code on the affected system.

No authentication required.
Triggered via network request.
Enables arbitrary code execution.

Live Threat

Current exploitation, exposure, and threat context

This SQL injection vulnerability in the application's backend component could allow an unauthenticated attacker to execute arbitrary code when they interact with the application through its network interface.

Application code execution.
Network-accessible application component.
System compromise.

Operational Fix

Recommended remediation, mitigation, and detection steps

This SQL injection vulnerability in FastAdmin's Backend.php component presents a critical risk that requires immediate attention. Owners of web applications utilizing FastAdmin should prioritize identifying all instances of this technology, assessing their business criticality and external reachability, and coordinating with relevant application and infrastructure teams to plan a secure remediation strategy.

Application and platform teams own the fix.
Verify application exposure and business impact.
Plan and execute secure code updates.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

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Frequently asked questions

What is Fastadmin and how is it used?

Fastadmin is a popular, open-source administrative framework based on PHP and the ThinkPHP framework. Developers use it to rapidly build backend management panels for web applications, providing a pre-built interface to manage data, user permissions, and system configurations.

What does CWE-89 mean for CVE-2026-51775?

CWE-89 identifies this issue as Improper Neutralization of Special Elements used in an SQL Command, commonly known as SQL injection. This means the application fails to properly filter user-supplied data before inserting it into database queries, allowing an attacker to manipulate the query logic to execute unauthorized code.

How does an attacker trigger this SQL injection?

An attacker triggers this vulnerability by sending a maliciously crafted network request to the Backend.php component within the Fastadmin framework. The vulnerability requires no authentication or user interaction to activate, though it cannot be triggered by legitimate, non-malicious traffic that adheres to expected data formats.

Do I need to worry about external access?

Yes. According to Halo Surface Signal, because Fastadmin serves as a web-based administrative framework, its components are often exposed via web interfaces. Any instance reachable over the internet is a potential target, as the flaw resides in a network-accessible backend controller.

What are the first steps to secure my Fastadmin instance?

Begin by identifying all servers running Fastadmin v.1.6.1.20250430 across your environment. Once mapped, assess which instances are accessible from the internet. Coordinate with your development or infrastructure teams to review available updates or security patches for the Backend.php component to neutralize the flaw.

References

gitee.com/Tor443/security-advisory/blob/master/README.md

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.