OAuthLib: Token grants can use attacker-supplied client_id for authorization after authenticating a different client
CVSS score
8.4
EPSS probability
—
Risk score
0.8
Published
2 h ago
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Vulnerability description
DayBreach AI Explanation
Verified against sourcesSources read
2
Source agreement
Tam uyum
Evidence confidence
%61
Short explanation
In OAuthLib versions prior to 4.0.0, token grant handlers can retain an attacker-supplied client_id after authenticating a different client, leading to incorrect authorization issues.
This vulnerability allows a lower-privilege authenticated client to cause grant and scope authorization to use another client's identity, potentially issuing tokens with unauthorized grants or scopes.
What should be done?
- Upgrade oauthlib to version 4.0.0 or later
- Use validators that authorize exclusively from request.client
- Follow vendor advisories and updates
The sources give limited detail on some technical conditions. Review the chain of evidence below before deciding how to act.
Chain of evidence and sources
OAuthLib 4.0.0 öncesi sürümlerde, token grant işleyicileri saldırgan tarafından sağlanan client_id değerini koruyabilir.
Bu zafiyet CWE-863 (Yanlış Yetkilendirme) kategorisindedir.
Show the technical text from the sources
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.
CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:H/SI:H/SA:N
CWE: CWE-863
This explanation was compiled automatically from the source records. Scores, active exploitation, patch and exploit status come straight from the sources.
IMPACT: Affected Products and Software
Affected Products
The following products are affected by CVE-2026-118669 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.
| ID | VENDOR | PRODUCT | ACTION |
|---|---|---|---|
| 1 | oauthlib | oauthlib | View |
RED HAT CSAF/VEX: Product Impact Check
SCORING: CVSS from Multiple Sources
CVSS Scores
The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.
| SCORE | VERSION | SEVERITY | VECTOR | SOURCE |
|---|---|---|---|---|
| 8.4 | CVSS V40 | HIGH | CVSS:4.0/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 | NVD |
| 8.4 | CVSS V4_0 | HIGH | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:H/SI:H/SA:N | CVE CNA |
Patch and Remediation Guide
Solution & Remediation Advisory
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Public exploit and active exploitation status
Verified exploit intelligence
No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.
Weakness Classification and Attack Patterns (CWE & CAPEC)
CWE - Common Weakness Enumeration
While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-118669 is associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-118669 weaknesses.
Attack Vector and Accessibility
Official Sources and Advisories
Similar Vulnerabilities
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