Threat researchers recently disclosed a severe vulnerability in a Figma Model Context Protocol (MCP) server, as reported by The Hacker News. While the specific patch is important, the discovery itself serves as a critical wake-up call for every organization rushing to adopt AI. This incident provides a blueprint for a new class of attacks that target the very infrastructure powering the AI Agent Economy.

To understand the risk, we must first look at the mechanics of this emerging threat.

What is MCP and Why is it a Target?

As businesses integrate AI agents, they require a means for these autonomous systems to communicate with existing applications. The Model Context Protocol (MCP) is a new protocol designed for this purpose, enabling an AI agent to interact with tools like Figma to perform tasks such as creating designs, modifying components, exporting assets, and more.

While powerful, these MCP servers create new, often unmonitored, pathways into sensitive corporate applications. An attacker who can compromise this channel isn't just bypassing a firewall; they are effectively impersonating a trusted AI agent to manipulate an application from the inside.

Anatomy of the Attack: Abusing the API Channel

The vulnerability allowed for a practical exploit that abused the API's intended functionality. The exploit chain followed a pattern that leveraged the API channel at every step to turn a legitimate feature into a weapon.

1. A Specific API Function Was Targeted: The vulnerability was identified in an API function within the MCP server, which was designed specifically for AI agents to retrieve data. This is a perfect example of a new, specialized API endpoint created for AI integration that may lack the mature security oversight of legacy systems.


2. A Command Was Injected into an API Parameter: The attack vector involved injecting a malicious OS command into a specific API parameter. By passing the command within a data field that the API function was expecting, such as one that specifies a file or resource ID, the malicious payload was delivered in a way that could bypass initial security checks.


3. Flawed Input Validation Was Exploited: The root cause of the vulnerability was a classic command injection flaw resulting from a failure in input validation. The application’s backend code took the data directly from the API parameter and executed it as part of a shell command without first sanitizing it. This critical oversight enabled an attacker to achieve Remote Code Execution (RCE), thereby gaining control over the server.


4. The AI Channel Could Be Used for Impact: With RCE confirmed, this compromised AI-to-application channel could be used for a wide range of malicious activities. An attacker could exfiltrate sensitive data, manipulate system files, or use the server as a beachhead to move deeper into the corporate network, all while appearing as legitimate traffic from an AI agent.

AI: An Unseen Risk Amplifier

This vulnerability is the tangible manifestation of the exact concerns security and development teams have about AI. Our latest 2025 State of API Security report found that a clear majority of organizations (56%) now view Generative AI as a growing security concern.

The reasons for this are directly related to incidents like this one:

• The top concern cited by respondents was a lack of control over the security of AI models used for code generation (56%). An MCP server is a prime example of a new, often poorly understood component introduced by AI integration.


• The second-highest concern was the difficulty in understanding and securing AI-generated code itself (47%).

Despite these fears, the push for innovation is relentless. 62% of organizations have already adopted GenAI for some or all of their API development. This creates a dangerous gap between the speed of adoption and the maturity of security practices. Unsurprisingly, this leaves security teams feeling unprepared. The report found that only 15% are "very confident" in their ability to detect and respond to attacks that leverage AI.

Preparing for the Next Wave of AI-Powered Threats

This vulnerability is not an isolated incident; it's a preview of what's to come. As AI agent adoption grows, attacks against the APIs and protocols that connect them will become more common.

Protecting against this new threat requires a purpose-built approach. At Salt Security, our platform provides the deep context needed to secure your AI transformation by delivering complete visibility into all API traffic, including new AI agent and MCP channels. We help you proactively improve your security posture by identifying the same kinds of misconfigurations and vulnerabilities exploited in this attack. Most importantly, our AI-powered behavioral threat protection baseline normalizes the activity of your AI agents to pinpoint and block sophisticated attacks in real-time, allowing you to innovate with AI securely.

If you want to learn more about Salt and how we can help you, please contact us, schedule a demo, or visit our website. You can also get a free API Attack Surface Assessment from Salt Security's research team and learn what attackers already know.

The post Anatomy of a Modern Threat: Deconstructing the Figma MCP Vulnerability appeared first on Security Boulevard.

Eric Schwake

Source: Security Boulevard
Source Link: https://securityboulevard.com/2025/10/anatomy-of-a-modern-threat-deconstructing-the-figma-mcp-vulnerability/