CVE-2026-118669 OAuthLib - Broken Access Control

OAuthLib < 4.0.0 contains a broken access control caused by client_credentials and Resource Owner Password Credentials grant handlers authenticating request.client incorrectly, letting lower-privilege clients obtain tokens with unauthorized grants or scopes, exploit requires attacker to be an authenticated client.

CVSS base score 8.4 /10
High
CISA KEV
Not listed
Public exploit
None known
Authentication
Required
View the NVD record ↗

Details

Type
Broken Access Control
Impact
Privilege Escalation
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/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
Published
28 October 2026
Updated
29 October 2026
Weakness
CWE-863

Vendor fix

Update to version 4.0.0 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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