GHSA-pfjf-5gxr-995x CVE-2026-28415 PYSEC-2026-65
Gradio has an Open Redirect in its OAuth Flow
Medium
PyPI
- Severity
- 4.3 / 10
- Medium · CVSS 3.1
- Exploit chance (EPSS)
- 0.29%
- Chance of exploitation in the next 30 days. Higher than 21.41% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-200 Exposure of Sensitive Information to an Unauthorized Actor
- CWE-284 Improper Access Control
- CWE-330 Use of Insufficiently Random Values
- CWE-601 URL Redirection to Untrusted Site ('Open Redirect')
- Fix
6.6.0- Upgrade gradio to this version or later
Description
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
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.
Affected versions
PyPI
| Package | Vulnerable | Fixed in |
|---|---|---|
| gradio | < 6.6.0 |
6.6.0 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
gradio PyPI → 6.6.0
- pip
pip install --upgrade "gradio>=6.6.0"- poetry
poetry add "gradio>=6.6.0"- uv
uv add "gradio>=6.6.0"
Severity breakdown
CVSS 3.1 4.3
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- Low
- Availability
- None
Weakness
CWE-200: Exposure of Sensitive Information to an Unauthorized Actor
The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.
How to prevent it
- Architecture and Design: Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.
CWE-284: Improper Access Control
The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.
How to prevent it
- Architecture and Design, Operation: Very carefully manage the setting, management, and handling of privileges. Explicitly manage trust zones in the software.
- Architecture and Design: Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.
CWE-330: Use of Insufficiently Random Values
The product uses insufficiently random numbers or values in a security context that depends on unpredictable numbers.
How to prevent it
- Architecture and Design: Use a well-vetted algorithm that is currently considered to be strong by experts in the field, and select well-tested implementations with adequate length seeds. In general, if a pseudo-random number generator is not advertised as being cryptographically secure, then it is probably a statistical PRNG and should not be used in security-sensitive contexts. Pseudo-random number generators can produce predictable numbers if the generator is known and the seed can be guessed. A 256-bit seed is a good starting point for producing a "random enough" number.
- Implementation: Consider a PRNG that re-seeds itself as needed from high quality pseudo-random output sources, such as hardware devices.
- Architecture and Design, Requirements: Use products or modules that conform to FIPS 140-2 [REF-267] to avoid obvious entropy problems. Consult FIPS 140-2 Annex C ("Approved Random Number Generators").
CWE-601: URL Redirection to Untrusted Site ('Open Redirect')
The web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect.
How to prevent it
- Implementation: Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright. Use a list of approved URLs or domains to be used for redirection.
- Architecture and Design: Use an intermediate disclaimer page that provides the user with a clear warning that they are leaving the current site. Implement a long timeout before the redirect occurs, or force the user to click on the link. Be careful to avoid XSS problems (CWE-79) when generating the disclaimer page.
- Architecture and Design: When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs. For example, ID 1 could map to "/login.asp" and ID 2 could map to "http://www.example.com/". Features such as the ESAPI AccessReferenceMap [REF-45] provide this capability.
- Architecture and Design: Ensure that no externally-supplied requests are honored by requiring that all redirect requests include a unique nonce generated by the application [REF-483]. Be sure that the nonce is not predictable (CWE-330).
- Architecture and Design, Implementation: Understand all the potential areas where untrusted inputs can enter your software: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide data to the application. Remember that such inputs may be obtained indirectly through API calls. Many open redirect problems occur because the programmer assumed that certain inputs could not be modified, such as cookies and hidden form fields.
- Operation: Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth [REF-1481].
References
Advisories
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-j36p-7w88-g82j Gradio FileExplorer preprocess path traversal allows files outside root_dir to reach callbacks | High | Also affects gradio |
| GHSA-6655-8ph2-63j3 Gradio: Audio cache key ignores metadata when saving numpy audio outputs | Low | Also affects gradio |
| GHSA-7hp7-4p35-3cx2 Gradio contains a cookie injection vulnerability | Medium | Also affects gradio |
| GHSA-jmh7-g254-2cq9 Gradio has SSRF via Malicious `proxy_url` Injection in `gr.load()` Config Processing | High | Also affects gradio |
| GHSA-39mp-8hj3-5c49 Gradio is Vulnerable to Absolute Path Traversal on Windows with Python 3.13+ | High | Also affects gradio |
| GHSA-h3h8-3v2v-rg7m Gradio: Mocked OAuth Login Exposes Server Credentials and Uses Hardcoded Session Secret | Medium | Also affects gradio |
| GHSA-8jw3-6x8j-v96g Gradio Allows Unauthorized File Copy via Path Manipulation | High | Also affects gradio |
| GHSA-wmjh-cpqj-4v6x Gradio CORS Origin Validation Bypass Vulnerability | Low | Also affects gradio |
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