CVE-2026-42560 CRITICAL

CVE-2026-42560: auth: Patreon provider assigns the same local user ID to every authenticated Patreon account, enabling cross‑user impersonation

Vendor Go-Pkgz
Product auth
Weakness CWE-287 · Improper authentication
Published May 9, 2026
Last update May 11, 2026

CVSS base score

9.1/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality High
Integrity High

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

What the vulnerability does

01Description

auth provides authentication via oauth2, direct and email. From versions 1.18.0 to before 1.25.2 and 2.0.0 to before 2.1.2, the Patreon OAuth provider maps every authenticated Patreon account to the same local user.ID, instead of deriving a unique ID from the Patreon account returned by Patreon. In practice, this means all Patreon-authenticated users of an application using this library are collapsed into a single local identity. Any application that trusts token.User.ID as the stable account key can end up mixing or fully merging unrelated Patreon users, which can lead to cross-account access, privilege confusion, and subscription-state leakage. This issue has been patched in versions 1.25.2 and 2.1.2.

Key dates

02Disclosure timeline

May 9, 2026 CVE published
May 11, 2026 Record updated