CVE-2026-28415 is a medium-severity (CVSS 4.3) Information Exposure vulnerability in gradio. A fix is available for gradio — see the affected versions and patch details below.
Gradio has Open Redirect in OAuth Flow
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-28415.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2026-28415 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 379,145 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
gradioReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
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 Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | gradio | all versions | 6.6.0pip install --upgrade 'gradio==6.6.0' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for gradio, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update gradio to 6.6.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-28415 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-28415 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-28415. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
This MODERATE impact vulnerability in Gradio's OAuth flow allows for open redirection due to an unvalidated `_target_url` query parameter. Red Hat products utilizing Gradio with OAuth enabled, such as the `ansible-chatbot-service`, may be affected if running vulnerable versions. Exploitation requires user interaction…
To mitigate this open redirect vulnerability, restrict network access to the Gradio application's `/logout` and `/login/callback` endpoints, particularly if OAuth is enabled. Ensure these endpoints are not directly exposed to untrusted networks or users. If the OAuth functionality is not required for the specific deployment of the Gradio application, consider disabling it to remove the vulnerable attack surface. Consult application documentation for specific configuration details regarding OAuth and endpoint exposure. A service restart or reload may be required for changes to take effect.Source: Red Hat security advisory for CVE-2026-28415 (CC BY 4.0)
Frequently Asked Questions
Is CVE-2026-28415 in your dependencies?
O3 Security finds CVE-2026-28415 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.