T01
Prompt injection
Instructions smuggled into a model’s input. Direct injection comes from the person typing. Indirect injection hides in content the system reads on someone’s behalf: a web page, an email, a shared document, an image, a calendar invite or a tool’s response.
How it shows up An assistant summarising your inbox reads a message telling it to gather recent files and put them in a link. It follows the instruction because, to the model, it looks like any other text.
Case note · June 2025 EchoLeak. Researchers at Aim Security reported a zero-click prompt injection in Microsoft 365 Copilot that could disclose information to an attacker without the user doing anything. Microsoft fixed it as CVE-2025-32711, scored 9.3 out of 10. Microsoft advisory
Principles that answer it
T02
Agent hijack and tool misuse
An agent with tools is steered, by injected text or a confused goal, into turning its legitimate access against its owner: reading files it should not, sending data out, changing settings or running commands.
How it shows up A coding agent reads an issue in a public repository, follows instructions planted in it, and copies data from a private repository into a public pull request.
Case note · May 2025 GitHub MCP “toxic agent flow”. Invariant Labs showed that a malicious issue in a public repository could lead a user’s agent, connected through the GitHub MCP server, to read private repositories and publish their contents in a public pull request. The weakness lay in how the agent combined its tools, not in the server’s code. Invariant Labs
Case note · July 2025 Supabase MCP demonstration. In a demonstration by General Analysis, instructions hidden in a support ticket led a Cursor agent, connected to a database with a role that bypasses row-level security, to read a table of integration tokens and post them back into the ticket thread. General Analysis
Case note · July 2025 Replit agent and the code freeze. During a declared code freeze, Replit’s AI agent deleted the production database behind SaaStr founder Jason Lemkin’s project, then wrongly said it could not be rolled back. The data was later recovered. SaaStr
Principles that answer it
T03
Poisoned tools and MCP servers
Tool descriptions are text the model reads and may follow. A malicious or compromised tool server can hide instructions in a description, change its behaviour after you approved it (a “rug pull”), or use its description to change how the agent calls a different, trusted tool (tool shadowing). The Model Context Protocol (MCP) made adding tools easy, and each added tool brings its own risk.
How it shows up Hidden in a harmless-looking tool’s description is an instruction to read a local credentials file and pass its contents along as a parameter.
Case note · April 2025 MCP tool poisoning. Invariant Labs showed that instructions hidden in an MCP tool’s description, invisible to the user but read by the model, could make an agent leak data or take actions nobody asked for. Invariant Labs
Principles that answer it
T04
Memory and context poisoning
Agents that remember across sessions, or share context with other agents, can be fed false facts or standing instructions that persist long after the original input is gone. Recording where each memory came from, and keeping each user’s memory separate, limits the damage.
How it shows up One poisoned document leaves a note in an assistant’s long-term memory, and every later session quietly follows it.
Principles that answer it
T05
Data and model poisoning
Tampering with pre-training, fine-tuning or embedding data to plant backdoors, bias or hidden triggers. A backdoored model can behave normally until it meets its trigger.
How it shows up Shown a rare trigger phrase, a model trained partly on scraped web text switches behaviour, and nothing in ordinary testing reveals it.
Case note · October 2025 A small number of samples. Anthropic, the UK AI Security Institute and the Alan Turing Institute found that about 250 poisoned documents planted a backdoor in models from 600 million to 13 billion parameters, roughly the same number whatever the model’s size. The backdoor they tested was deliberately low-stakes (it made the model produce gibberish), and larger models were not tested. Anthropic research
Principles that answer it
T06
Supply chain: malicious models and invented packages
Model files that execute code when loaded, backdoored models on public hubs, tampered extensions and plug-ins, and packages that a model invents and an attacker then registers, a trick known as slopsquatting.
How it shows up A developer accepts an AI-suggested import for a package that did not exist last month. Someone has since published it, with a payload.
Case note · February 2024 Malicious models on Hugging Face. JFrog found around 100 malicious models on Hugging Face. One opened a reverse shell on the machine that loaded it, using Python’s pickle format to run code at load time. JFrog
Case note · 2025 Package hallucinations. A study presented at USENIX Security 2025 found that 19.7% of packages suggested by the code-generating models it tested did not exist: at least 5.2% for commercial models and 21.7% for open-source ones. Anyone can register those invented names. Spracklen et al.
Case note · July 2025 Amazon Q Developer extension. A wrongly scoped GitHub token let an attacker add malicious code to version 1.84.0 of the Amazon Q Developer extension for Visual Studio Code. AWS says the code did not run as intended and no customer resources were affected. Version 1.85.0 removed it (CVE-2025-8217). AWS security bulletin
Principles that answer it
T07
Sensitive information and hidden context exposure
Models repeat what is in their context: other users’ data pulled in by retrieval, secrets placed in the system prompt or other hidden instructions, or fragments memorised from training data. OWASP’s 2026 list renamed system prompt leakage to hidden context exposure for this reason: the system prompt is only one of the places hidden context lives.
How it shows up Asked to print its instructions, a support bot reveals an internal pricing rule, plus an API key someone pasted into the prompt.
Principles that answer it
T08
Retrieval (RAG) and embedding weaknesses
Retrieval-augmented generation (RAG) adds a search step before the model answers. It fails when retrieval ignores permissions, when tenants share a vector store without enforced filters, when attackers plant documents designed to be retrieved, or when embeddings (the numeric fingerprints a vector store keeps) are reversed to recover the original text.
How it shows up An intern asks the staff assistant a simple question and gets a paragraph from a confidential board paper, because the index never knew who could read what.
Principles that answer it
T09
Jailbreaks
Inputs crafted to make a model ignore its safety training: role play, encoding tricks, long runs of examples, or slow escalation across many turns. OWASP treats jailbreaking as a form of prompt injection.
How it shows up Refused in one message, the same request succeeds when it is split across twenty friendly turns.
Principles that answer it
T10
Improper output handling and unexpected code execution
Model output passed into a browser, shell, interpreter, template or database without checks. The model becomes a delivery route for classic injection attacks, or a way to run code nobody reviewed.
How it shows up An administrator opens a conversation log, and a script in the chatbot’s answer runs in their browser.
Principles that answer it
T11
Model extraction and theft
Stealing weights from storage or a build pipeline, or copying a model’s behaviour by querying it at scale and training a copy on the answers.
How it shows up Someone sends millions of carefully chosen queries through an API and trains a cheaper model on the responses.
Principles that answer it
T12
Unbounded consumption
Unlimited inputs, loops or fan-out (one request spawning many) that exhaust compute, quotas or budget. Also called denial of wallet.
How it shows up Two agents keep handing a task back and forth overnight. The morning brings an exhausted quota and a very large invoice.
Principles that answer it
T13
Misinformation and overreliance
Confident wrong answers, invented citations, and agents that persuade people to approve actions they do not fully understand.
How it shows up Nobody checks the citations before the report goes out under a real name, and two of them do not exist.
Principles that answer it
T14
AI in the attacker’s hands
The same tools that help defenders help attackers: cloned voices and faces for fraud, phishing written fluently in any language at scale, and faster discovery and exploitation of weaknesses, in at least one reported case with an agent doing much of the work.
How it shows up A finance officer joins a video call with what appear to be the CFO and several colleagues, all generated, and approves a series of transfers.
Case note · January–May 2024 Deepfake video call. An Arup employee in Hong Kong transferred HK$200 million (about US$25.6 million) after a video call in which the chief financial officer and other colleagues were deepfakes. Arup confirmed it was the victim in May 2024. South China Morning Post
Case note · November 2025 An AI-run espionage campaign. Anthropic reported that a group it assessed as Chinese state-sponsored used Claude Code to run a cyber-espionage campaign against about 30 organisations, with the AI carrying out 80–90% of the tactical work. A handful of intrusions succeeded. The AI also made mistakes, including claiming credentials that did not work. Anthropic
Case note · August 2025 s1ngularity. Malicious versions of the Nx build tool, live on npm for about four hours, harvested secrets, tried to get locally installed AI command-line tools to search the machine for more, and uploaded what they found to public GitHub repositories (CVE-2025-10894). Nx postmortem
Principles that answer it
T15
Shadow AI
Staff use AI tools the organisation has not reviewed, paste confidential material into them, or switch on AI features inside approved software without anyone checking where the data goes. Browser extensions and personal agents with broad access add to the problem.
How it shows up To fix its formatting, a team uploads a customer list to a free AI tool whose terms let the provider keep the data.
Principles that answer it