CVE-2026-49272
OAuthLib: Bearer token can be retrieved as long as client knows a valid client ID for device workflow
OAuthLib is an implementation of the OAuth request-signing logic for Python 3.6+. From 3.3.0 until 4.0.1, OAuthLib's RFC 8628 device workflow does not require DeviceCodeGrant.validate_token_request to check that the device_code parameter is present and valid. A caller whose client request is accepted by the configured validator and who knows a valid client ID enabled for the device workflow can submit a missing or bogus device code to the token endpoint and obtain a bearer token without completing device authorization. This issue is fixed in version 4.0.1.
Fixes and workarounds
Fix
oauthlib (PyPI): OSV reports a fixed version 4.0.0. Check the advisory for supported release branches.
Source: OSV GHSA-3jp2-3mrg-2vxcAffected products and versions
| Product | Versions | Authority |
|---|---|---|
| oauthlib oauthlib |
>= 3.3.0, < 4.0.1 (affected) | CNA: GitHub_M |
oauthliboauthlib
PyPI |
3.3.0 (affected, PyPI) 3.3.1 (affected, PyPI) Ecosystem version events: introduced 3.3.0; fixed 4.0.0 Source events (ECOSYSTEM)Other versions: unaffected |
OSV GHSA-3jp2-3mrg-2vxc |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 3.1 / 8.5 high |
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:H/A:N | CNA: GitHub_M |
Exploit evidence
- https://github.com/oauthlib/oauthlib/security/advisories/GHSA-3jp2-3mrg-2vxc
exploit · ADP: CISA-ADP
References
- https://github.com/oauthlib/oauthlib/security/advisories/GHSA-3jp2-3mrg-2vxcCNA: GitHub_M · x_refsource_CONFIRM
- https://github.com/oauthlib/oauthlib/pull/954CNA: GitHub_M · x_refsource_MISC
- https://github.com/oauthlib/oauthlib/commit/77a5f1c8ce00da2b0b8c5f6e9cc129920085f114CNA: GitHub_M · x_refsource_MISC
- https://github.com/oauthlib/oauthlib/releases/tag/v4.0.1CNA: GitHub_M · x_refsource_MISC
- https://github.com/oauthlib/oauthlib/security/advisories/GHSA-3jp2-3mrg-2vxcADP: CISA-ADP · exploit
- https://github.com/advisories/GHSA-3jp2-3mrg-2vxcOSV / GitHub Security Advisories · advisory
- https://osv.dev/vulnerability/GHSA-3jp2-3mrg-2vxcOSV / GitHub Security Advisories · osv
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