Gradio has an Open Redirect in its OAuth Flow

# Summary The _redirect_to_target() function in Gradio's OAuth flow accepts an unvalidated _target_url query parameter, allowing redirection to arbitrary external URLs. This affects the /logout and /login/callback endpoints on Gradio apps with OAuth enabled (i.e. apps running on Hugging Face Spaces with gr.LoginButton). ## Details ```python def _redirect_to_target(request, default_target="/"): target = request.query_params.get("_target_url", default_target) return RedirectResponse(target) # No validation ``` An attacker can craft a URL like https://my-space.hf.space/logout?_target_url=https://evil.com/phishing that redirects the user to an external site after logout. Because the URL originates from a trusted hf.space domain, users are more likely to trust the link. ## Impact Phishing , an attacker can use the trusted domain to redirect users to a malicious site. No direct data exposure or server-side impact. ## Fix The _target_url parameter is now sanitized to only use the path, query, and fragment, stripping any scheme or host.

CVSS 3.1

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

Severity from

GitHub (reviewed advisory)

Weakness

CWE-200, CWE-284, CWE-330, CWE-601

Also known as

CVE-2026-28415, PYSEC-2026-65

• github.com/gradio-app/gradio/security/advisories/GHSA-pfjf-5gxr-995x
• nvd.nist.gov/vuln/detail/CVE-2026-28415
• github.com/gradio-app/gradio/commit/dfee0da06d0aa94b3c2684131e7898d5d5c1911e
• github.com/gradio-app/gradio
• github.com/gradio-app/gradio/releases/tag/gradio%406.6.0
• github.com/pypa/advisory-database/tree/main/vulns/gradio/PYSEC-2026-65.yaml