What’s Vulnerable › Vulnerabilities
CVE-2026-27167: Gradio: Mocked OAuth Login Exposes Server Credentials and Uses Hardcoded Session Secret
- Severity: medium (CVSS 5.9 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.5% probability of exploitation in the next 30 days
- Public exploit or detection template: yes
- Published: 2026-02-27 · updated 2026-06-17
- Weakness: CWE-522
Description
Gradio is an open-source Python package designed for quick prototyping. Starting in version 4.16.0 and prior to version 6.6.0, Gradio applications running outside of Hugging Face Spaces automatically enable "mocked" OAuth routes when OAuth components (e.g. `gr.LoginButton`) are used. When a user visits `/login/huggingface`, the server retrieves its own Hugging Face access token via `huggingface_hub.get_token()` and stores it in the visitor's session cookie. If the application is network-accessible, any remote attacker can trigger this flow to steal the server owner's HF token. The session cookie is signed with a hardcoded secret derived from the string `"-v4"`, making the payload trivially decodable. Version 6.6.0 fixes the issue.
Affected products
- gradio-app gradio: from 4.16.0 before 6.6.0 — fixed in 6.6.0
How to fix
Upgrade to a fixed version: gradio-app gradio 6.6.0. Check the vendor advisory for mitigations.
References
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