SB2026102503 - Improper Authentication in oauthlib

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Main Vulnerability Database SB2026102503

SB2026102503 - Improper Authentication in oauthlib

Published: October 25, 2026

Security Bulletin ID SB2026102503
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Data manipulation

Breakdown by Severity

Medium 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Improper Authentication (CVE-ID: CVE-2026-49272)

CWE-ID: CWE-287 - Improper Authentication

CVSSv4: 7.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a remote user to obtain a bearer token without a valid device code and gain unauthorized access to resources accessible with that token.

The vulnerability exists due to missing device code validation in oauthlib's DeviceCodeGrant.validate_token_request method when processing device authorization grant requests. A remote user can submit a token endpoint request containing a valid client_id enabled for the device workflow, grant_type="urn:ietf:params:oauth:grant-type:device_code", and an arbitrary device_code to obtain a bearer token without completing the required device authorization.


Remediation

Install update from vendor's website.

References