When AI Agents Trust the Dead: More Than 900 MCP Servers Pointing to Hijackable GitHub Repositories
Key Takeaways
- We health-checked more than 90,000 unique GitHub URLs across four major MCP (Model Context Protocol) directories and found that roughly 8% are dead, with more than 900 of those dead links pointing to deleted GitHub accounts that anyone can register with no exploit required.
- More than a quarter (27%) of the hijackable surface came from the top 10 claimable accounts, accounting for more than 240 repositories. A single username was observed claiming up to 92 repositories.
- More than 80 of the hijackable entries are named after well-known services like AWS, MySQL, PayPal, Shopify, and Telegram, the exact names users search for. We did not find evidence that the directories we examined routinely validate link health, detect namespace changes, or verify code integrity at listed URLs.
- As AI agents increasingly discover and install MCP servers on their own with no human reading the README or noticing a new owner, this attack is shifting from tricking a user to tricking an agent, a risk the NSA’s AI Security Center flagged in a May 2026 advisory on MCP security design flaws.
In our new research, we scrutinize the security of Model Context Protocol (MCP) server directories, the community platforms where developers find and install AI agent tools.
After sampling or crawling four major directories and health-checking more than 90,000 GitHub URLs in September 2026, we found that more than 900 dead links point to deleted GitHub accounts. The usernames of these accounts can be re-registered by an attacker, inheriting the trust and visibility of every directory listing that still links to them without the need for an exploit.
What we discovered
To start an attack, an attacker needs only a GitHub account. Zero technical sophistication needed: no vulnerability research, no exploit development, no malware obfuscation. Because this doesn’t involve a software vulnerability, there’s no straightforward fix like patching.
Potentially hijackable links
Upon checking more than 90,000 unique GitHub URLs, we found that one in every 13 MCP server links points to a repository that no longer exists. Out of the more than 7,000 that are dead, more than 900 are potentially hijackable.
Impersonating trusted services
More than 80 of the identified hijackable entries are named after well-known services and platforms. This makes the attack even more dangerous, as the popular services are often the names users would search for in a directory.
The big names include databases such as MySQL and PostgreSQL, dev platforms such as GitHub and Jenkins, and cloud and infrastructure platforms such as AWS and Cloudflare.
| Service category | Count | Namesake services and platforms | Risk category | Risk profile |
|---|---|---|---|---|
| Dev platforms | 16 | GitHub, GitLab, Jenkins, WordPress, and other dev tools | Trust and identity | Developer tooling integration |
| Cloud and infra | 14 | AWS, Supabase, Cloudflare, Netlify, and other cloud providers | Infrastructure and data | Cloud credentials and infra access keys |
| Databases | 12 | MySQL, PostgreSQL, MongoDB, and other popular databases | Infrastructure and data | Users connect with real database credentials |
| Productivity | 8 | Microsoft 365, Notion, Jira, Obsidian, and other enterprise tools | AI and productivity data | Enterprise and academic user data |
| Social and messaging | 8 | Twitter/X, Discord, Telegram, Slack, and other social platforms | Trust and identity | OAuth tokens, message history at risk |
| AI/ML | 7 | OpenAI, Grok, Gemini, and other LLM providers | AI and productivity data | Multi-model AI routed through attacker |
| Crypto/DeFi | 6 | Solana, Ethereum, Binance, and other blockchain networks | Financial exposure | Direct financial exposure (wallet keys) |
| Commerce and payments | 5 | Shopify, Stripe, PayPal, and other ecommerce platforms | Financial exposure | Store credentials, payment data exposed |
| 3D and gaming | 5 | Unity, Unreal, Blender, and other 3D/game engines | Infrastructure and data | Developer workstation access |
When the installer is an AI agent
When, instead of a human, an AI agent serves as the installer, the AI agent might be easier to trick. For example, a human might notice details such as suspicious instructions in the README or the newness of the account, or take note of reputation signals such as stars and forks. By contrast, an autonomous agent might not evaluate these signals in the same way. This poses greater risk.
| Checkpoint | Human installer | Autonomous agent |
|---|---|---|
| Reads the README | Skims it; may notice odd or suspicious instructions. | Parses it as context to act on, including any injected instructions. |
| Notices a new owner | May spot a brand-new account, a recently created repo, or a changed profile. | Has no memory of what the account looked like last month. |
| Judges reputation | Weighs stars, forks, and familiar names. | Matches on name and description, exactly the fields the attacker controls. |
| Speed and volume | Installs occasionally, one server at a time. | Can evaluate and connect many servers per session, across many users. |
| Sees the result | May notice errors or strange behavior. | Tool output flows straight into its context; failures are often retried silently. |
Why this matters for organizations
Because MCP servers sit behind a large language model (LLM), attackers can use prompt injection to manipulate the AI into invoking tools on other connected servers. This turns a single compromised server into a cross-service attack, no traditional exploit code required.
| Capability | What the attacker gets |
|---|---|
| Arbitrary code execution | Local process with the user's OS privileges; no sandbox. |
| File system access | Read/Write any file the user owns: SSH keys, AWS credentials, .env files, source code. |
| Credential harvesting | MCP configuration files store API keys for ALL configured servers in plaintext. |
| Lateral movement via config | A single malicious server can read the config and extract credentials for every other MCP server installed. |
| Network exfiltration | Outbound HTTP to any host. Silent data exfiltration with no network policy enforcement. |
| LLM context injection | Server responses feed directly into the AI's context window. Prompt injection from inside the tool chain. |
| Persistence | MCP servers auto-start with the AI assistant. Attacker's code runs every session. |
Download the full report
Read our technical brief for the full breakdown of our findings and our detection, mitigation, and defense recommendations.