PYSEC-2026-1682

I. Detailed Description:

This includes scenarios, screenshots, vulnerability reproduction methods. For account-related vulnerabilities, please provide test accounts. If the reproduction process is complex, you may record a video, upload it to Taopan, and attach the link.

1. Install ms-swift

   pip install ms-swift -U
   

2. Start web-ui

   swift web-ui --lang en
   

3. After startup, access through browser at http://localhost:7860/ to see the launched fine-tuning framework program

4. Fill in necessary parameters In the LLM Training interface, fill in required parameters including Model id, Dataset Code. The --output_dir can be filled arbitrarily as it will be modified later through packet capture

5. Click Begin to start training. Capture packets and modify the parameter corresponding to --output_dir

   You can see the concatenated command being executed in the terminal where web-ui was started

6. Wait for the program to run (testing shows it requires at least 5 minutes), and you can observe the effect of command execution creating files

II. Vulnerability Proof (Write POC here):

/tmp/xxx'; touch /tmp/inject_success_1; #

III. Fix Solution:

1. The swift.ui.llm_train.llm_train.LLMTrain#train() method should not directly concatenate parameters with commands after receiving commands from the frontend
2. The swift.ui.llm_train.llm_train.LLMTrain#train_local() method should not use os.system for execution, but should be changed to subprocess.run([cmd, arg1, arg2...]) format

Author

• Discovered by: TencentAISec
• Contact: security@tencent.com