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Public proof of conceptFix availableAwaiting NVD analysis

CVE-2026-49272

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

A public proof of concept exists; no exploitation attested.

  • Published2026-11-05
  • Fixed in4.0.1
  • WeaknessCWE-287

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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.

Timeline

dates in UTC
  1. 2026-11-0520:58CVE publishedCNA

Versions per branch

OSV
oauthlib
BranchAffectedFixed in
4.0≥ 3.3.0, < 4.0.14.0.1

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Products declared by the CNA1 product

As GitHub_M, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

  • oauthlib
    Affected
    • = >= 3.3.0, < 4.0.1no fix stated

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-11-05

Fix

  1. Update oauthlib to 4.0.1

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • CISA-ADPSSVC decisionpoc2026-11-05
  • CNACVSS 3.18.52026-11-05
  • CNAweakness (CWE)CWE-2872026-11-05
  • NVDweakness (CWE)CWE-287read 2026-11-05
  • OSVaffected packages—
  • GitHub AdvisoriesadvisoryHIGH2026-10-27

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:H/A:N
Published
2026-11-05
Last Modified
2026-11-05
NVD status
Received
GitHub Advisory
GHSA-3jp2-3mrg-2vxc

Frequently asked questions

What is CVE-2026-49272?

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.

Is CVE-2026-49272 actively exploited?

A proof-of-concept exploit exists for CVE-2026-49272, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2026-49272?

CVE-2026-49272 has a CVSS v3 base score of 8.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:H/A:N.

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