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CVE-2026-49272— OAuthLib: Bearer token can be retrieved as long as client knows a valid client ID for device workflow

Quick assessment

Affected
oauthlib oauthlib
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

OAuthLib 是面向 Python 3.6 及以上版本的 OAuth 请求签名逻辑实现。在 3.3.0 至 4.0.1 版本中，OAuthLib 的 RFC 8628 设备工作流程未要求 DeviceCodeGrant.validate_token_request 检查 device_code 参数是否存在且有效。因此，若调用方的客户端请求已通过配置的验证器，且其知晓一个已启用设备工作流程的有效客户端 ID，则该调用方可向令牌端点提交缺失或伪造的 device_code，从而在未完成设备授权的情况下获取 Bea

CVSS 8.5 · High

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application
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I. Basic Information for CVE-2026-49272

Vulnerability Information
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Vulnerability Title
OAuthLib: Bearer token can be retrieved as long as client knows a valid client ID for device workflow
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:H/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
认证机制不恰当
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
oauthlib oauthlib >= 3.3.0, < 4.0.1 -

II. Public POCs for CVE-2026-49272

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III. Intelligence Information for CVE-2026-49272

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Other References for CVE-2026-49272 (4)

IV. Related Vulnerabilities

Same product: oauthlib
Same vendor: oauthlib
Same weakness: CWE-287