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Fencer Intel
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CVE-2026-27167 json

Gradio: Mocked OAuth Login Exposes Server Credentials and Uses Hardcoded Session Secret

published 8mo ago modified 4mo ago also EUVD-2026-9075 , GHSA-h3h8-3v2v-rg7m , PYSEC-2026-63

cvss
0.0
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 43%
public exploits
0
none known

Summary

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.

Patch / fix

  • pypi gradio 6.6.0
  • gradio-app gradio 6.6.0
  • gradio_project gradio 6.6.0

Is CVE-2026-27167 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-27167 updated cvss 3.7

Gradio: Gradio: Information disclosure due to hardcoded secret in session cookie signing, allowing remote attackers to steal Hugging Face tokens.

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
8mo ago

Exploit prediction

0.51% chance of exploitation in the next 30 days, higher than 43% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/gradio-app/gradio/security/advisories/GHSA-h3h8-3v2v-rg7m referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 0.0 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:N
GitHub 3.1 0.0 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:N
NVD 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
OSV 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected packages

ecosystem package affected fixed in
pypi gradio
>=4.16.0, <6.6.0
6.6.0

Affected products

  • gradio-app gradio

Classification

Weakness
  • CWE-798 Use of Hard-coded Credentials
  • CWE-522 Insufficiently Protected Credentials

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.