CVE-2026-118669：OAuthLib 令牌授權可被攻擊者利用偽造 client_id 取得未授權許可權
CVE-2026-118669 - OAuthLib: Token grants can use attacker-supplied client_id for authorization after authenticating a different client
OAuthLib 在 4.0.0 之前的版本中，token 授權處理可能被低許可權客戶端利用偽造 client_id 取得未授權許可權。
此 CVE 說明 OAuthLib 在 token 授權時可能被攻擊者利用低許可權客戶端偽造身份，建議立即升級至 4.0.0 並審查驗證邏輯。
OAuthLib is an implementation of the OAuth request-signing logic for Python 3.6+. Prior to 4.0.0, the client_credentials and Resource Owner Password Credentials token grant handlers can authenticate request.client as one confidential client while retaining an attacker-supplied request.client_id for validate_grant_type and validate_scopes. A lower-privilege authenticated client can therefore cause grant and scope authorization to use another client's identity when an application validator relies on the documented client_id argument, potentially issuing tokens with unauthorized grants or scopes. Validators that authorize exclusively from request.client may not be affected. This issue is fixed in version 4.0.0.
Impact
Affected Products
The following products are affected by CVE-2026-118669
vulnerability.
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No affected product recoded yet
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | HIGH | [email protected] |
Upgrade OAuthLib to version 4.0.0 or later to fix client authentication issues.
- Update OAuthLib to version 4.0.0 or later.
- Review and update application validators for client authentication.
- Ensure validators exclusively use request.client for authorization.
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CVE-2026-118669.
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-118669 is
associated with the following CWEs:
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approaches employed by adversaries to exploit the CVE-2026-118669
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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CVE-2026-118669 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-118669 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by [email protected]
十月. 28, 2026
Action Type Old Value New Value Added Description OAuthLib is an implementation of the OAuth request-signing logic for Python 3.6+. Prior to 4.0.0, the client_credentials and Resource Owner Password Credentials token grant handlers can authenticate request.client as one confidential client while retaining an attacker-supplied request.client_id for validate_grant_type and validate_scopes. A lower-privilege authenticated client can therefore cause grant and scope authorization to use another client's identity when an application validator relies on the documented client_id argument, potentially issuing tokens with unauthorized grants or scopes. Validators that authorize exclusively from request.client may not be affected. This issue is fixed in version 4.0.0. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:H/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-863 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/118xxx/CVE-2026-118669.json">CVE-2026-118669</a> Added Reference https://github.com/oauthlib/oauthlib/commit/c951a1d09f99f14e3240973fa83c4f4287d4753d Added Reference https://github.com/oauthlib/oauthlib/pull/920 Added Reference https://github.com/oauthlib/oauthlib/releases/tag/v4.0.0 Added Reference https://github.com/oauthlib/oauthlib/security/advisories/GHSA-7984-qgvg-3j9c
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.