The Institute of the Estonian Language has released a benchmark measuring how susceptible AI language models are to Russian propaganda. Sixty models were tested with 75 questions in three languages covering 14 propaganda narratives, phrased in neutral, biased, and manipulative ways. Each answer is scored on a scale of 1 to 5, where 1 means the model repeats Russian talking points.

A calibrated Claude Opus 4.5 served as the evaluation model, validated by disinformation experts at the organization Propastop. Anthropic's Claude models claimed the top spots, followed by Nvidia's Nemotron 3 and Alibaba's Qwen 3.6 Plus. Mistral's models, including the newest Medium 3.5, landed in the bottom third. The models had no access to web search or other tools during testing, so the benchmark only measures how well the language model itself can spot and reject propaganda.

The results line up with a Newsguard study that found Mistral had a steady misinformation rate of 36.67 percent. That's a bad look for the French company, which positions itself as a European alternative to US and Chinese providers and is currently negotiating a 3 billion euro funding round at a 20 billion euro valuation. It's especially rough since Mistral's flagship models already struggle to keep up with the competition.

The threat is real. Russian networks like "Pravda" deliberately feed AI systems millions of disinformation articles. And OpenAI recently shut down a Russian campaign that used ChatGPT to spread propaganda ahead of Germany's federal election.