# CVE-2026-27167: Gradio: Mocked OAuth Login Exposes Server Credentials and Uses Hardcoded Session Secret

> Remote attackers can steal server Hugging Face tokens via mocked OAuth routes using a hardcoded session secret in Gradio applications.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 27 Feb 2026
- **Updated:** 2 Mar 2026
- **Also known as:** GHSA-h3h8-3v2v-rg7m, PYSEC-2026-63

## What is CVE-2026-27167?

CVE-2026-27167 is a vulnerability in Gradio Project Gradio, published on 27 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-798 (Use of Hard-coded Credentials), CWE-522 (Insufficiently Protected Credentials)

## Which versions are affected by CVE-2026-27167?

3 open source packages ship an affected version, including gradio. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `gradio` | PyPI | From 4.16.0 | 6.6.0 |
| `gradio` | PyPI | From 4.16.0 | 6.6.0 |
| `gradio` | PyPI | From 4.16.0 | 6.6.0 |

Products: Gradio Project Gradio.

## How do I fix CVE-2026-27167?

Upgrade gradio to 6.6.0 or later.

## Is CVE-2026-27167 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-27167 exists.

## Other vulnerabilities in Gradio Project Gradio

- [CVE-2024-39236](https://insights.sbomify.com/CVE-2024-39236/): Withdrawn Advisory: Gradio was discovered to contain a code injection vulnerability via the component /gradio/component_meta.py (critical 9.8)
- [CVE-2023-6572](https://insights.sbomify.com/CVE-2023-6572/): Command Injection in gradio-app/gradio (critical 9.6)
- [CVE-2022-24770](https://insights.sbomify.com/CVE-2022-24770/): Improper Neutralization of Formula Elements in a CSV File in Gradio Flagging (high 8.8)
- [CVE-2026-49119](https://insights.sbomify.com/CVE-2026-49119/): Gradio < 6.16.0 Path Traversal via FileExplorer.preprocess() (high 8.7)
- [CVE-2025-23042](https://insights.sbomify.com/CVE-2025-23042/): Gradio Blocked Path ACL Bypass Vulnerability (high 8.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-27167 and fix it if it is affected.

What it is: CVE-2026-27167 is a vulnerability in Gradio Project Gradio, published on 27 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-27167 exists.

Affected packages and fixed versions:
- gradio (PyPI): affected from 4.16.0; fixed in 6.6.0
- gradio (PyPI): affected from 4.16.0; fixed in 6.6.0
- gradio (PyPI): affected from 4.16.0; fixed in 6.6.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-27167/ (Markdown: https://insights.sbomify.com/CVE-2026-27167/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-27167
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-27167
- OSV: https://osv.dev/vulnerability/CVE-2026-27167

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-27167/
Summaries are generated and may contain mistakes; the official description above is the record.