Executive brief
F5-TTS is an open-source text-to-speech system. A security flaw in its fine-tuning interface allows unauthenticated remote users to create folders and write files anywhere on the server's filesystem that the application has permission to access. This could allow an attacker to disrupt operations or potentially gain further control over the server by overwriting critical configuration files.
Technical details
A path traversal vulnerability exists in the Gradio-based fine-tuning handlers of F5-TTS (specifically within functions like create_data_project and save_settings). The root cause is the unsafe use of os.path.join() with unsanitized user-supplied project names. In Python, if an argument to os.path.join() is an absolute path, all previous components are discarded. An unauthenticated remote attacker can exploit this by providing an absolute path (e.g., /tmp/EVIL) as a project name, allowing them to create directories and write JSON content outside the intended base directory. The vulnerability is fixed in commit 2f53ded by implementing a path validation helper that rejects absolute paths and verifies the resolved path remains within the expected base directory.
Affected products
- SWivid F5-TTS through 1.1.20
Timeline
- 2026-05-12: disclosed: Issue reported to maintainer via GitHub
- 2026-05-13: patched: Fix merged into main branch via commit 2f53ded
- 2026-06-01: advisory: CVE published to NVD