# Backdooring Open-Weight AI Models

> Source: <https://www.schneier.com/blog/archives/2026/10/backdooring-open-weight-ai-models.html>
> Published: 2026-10-16 11:04:53+00:00

[This](https://projectdiscovery.io/research/how-abliterated-models-can-get-you-pwned) is a problem:

Any open model whose weights have been edited can carry a backdoor, whether it’s a task-specific fine-tune, a merged adapter or an abliterated build. We have abliterated models in the title because it’s the most popular reason people download modified weights without verifying what’s inside. Abliteration is a cheap fine-tune that takes away a model’s ability to refuse. You find the direction in the weights that carries “no” and subtract it. The model then answers things a safety-tuned version would turn down. It began as a research trick and it’s now routine before people upload a model to Hugging Face, where you’ll find abliterated builds of most of the popular open weights: Qwen, Llama, even OpenAI’s gpt-oss...