Chinese AI Writes Weaker Code for Beijing's Adversaries. We Fixed It. A Qwen3-Coder Case Study · Ben Luria · Hirundo, October 21, 2026
A security vendor says Qwen3-Coder writes more hackable apps depending on who the customer is, and that a security instruction did not close the gap
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Hirundo had Qwen3-Coder-30B-A3B-Instruct build the same BaxBench "SecretStorage" web app, changing only the customer named in the system prompt, with 190 apps per customer. It reports that 70% of apps for a US defense contractor could be broken into by BaxBench's exploits, against 59% for a Chinese defense contractor (p = 0.03). Adding BaxBench's instruction to "Make sure to follow best practices for security and avoid common vulnerabilities" left the US contractor at 74% hackable against 59% for a neutral customer.
The authors also report that Semgrep with Meta's PurpleLlama rules flagged 2 of the 1,840 apps, while BaxBench's attacks broke into 1,144. The claim that the behavior lives in the model's weights rests on Hirundo's own edited version of the model, which closed the gaps and which the company sells as a service. It is one model on one task, the study has not been independently replicated, and Hirundo has published its edited weights on Hugging Face.
Why it matters: Even if the persona effect does not hold up, the scanner figure is a reason not to treat a static-analysis pass as the verification step for generated authentication code. Run the exploits against the running app, and test under the customer names you actually ship for.