OAuthLib: Bearer token can be retrieved as long as client knows a valid client ID for device workflow

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

8.5 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:H/A:N

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Summary A call to the token endpoint with a grant type of `"urn:ietf:params:oauth:grant-type:device_code"` and a bogus `device_code` is able to get a bearer token as long as they know a valid client ID enabled for the device workflow.

Details Section 3.4 of the RFC 8628 spec says that the token endpoint should take in `device_code` as a required parameter.`DeviceCodeGrant.validate_token_request` does not perform any validation of `device_code`. `DeviceCodeGrant.validate_token_request` should be validating that `device_code` was passed in as a parameter and that it is valid, similar to how `AuthorizationCodeGrant.validate_token_request` does the checks here and…

Published by the source

27 Oct 2026, 13:30 UTC

Last modified by the source

27 Oct 2026, 13:45 UTC

Source last checked

28 Oct 2026, 06:20 UTC

1. Revision 2 · amended · 28 Oct 2026

   Amended from osv record GHSA-3jp2-3mrg-2vxc

2. Revision 1 · created · 27 Oct 2026

   Published from ghsa record GHSA-3jp2-3mrg-2vxc

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# Patch Next advisory brief: CVE-2026-49272

Advisory: OAuthLib: Bearer token can be retrieved as long as client knows a valid client ID for device workflow
IDs: CVE-2026-49272, GHSA-3jp2-3mrg-2vxc
Record: https://patchnext.com/advisories/cve-2026-49272 (revision 2, source checked 28 Oct 2026, 06:20 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: oauthlib 4.0.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI oauthlib: affected >= 3.3.0, < 4.0.0; fixed in 4.0.0

## Suggested inspection (read-only)
- `python -m pip show oauthlib`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on oauthlib.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-3jp2-3mrg-2vxc (OSV record GHSA-3jp2-3mrg-2vxc lists affected ranges: PyPI oauthlib >=3.3.0 <4.0.0 (fixed))
- Verified: https://github.com/advisories/GHSA-3jp2-3mrg-2vxc (GitHub-reviewed advisory GHSA-3jp2-3mrg-2vxc lists affected ranges: PyPI oauthlib >=3.3.0 <4.0.0)

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