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Vulnerability · Published May 9, 2026 · Assigned by GitHub_M

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

Critical 9.1

In plain English

A critical-severity improper authentication in auth from go-pkgz. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 36% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)9.1Critical
Exploit odds (30 days)0.4%top 63.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official description

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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Gogithub.com/go-pkgz/auth1.25.2GHSA-f6qq-3m3h-4g42
Gogithub.com/go-pkgz/auth1.25.2GO-2026-5348
Gogithub.com/go-pkgz/auth/v22.1.2GHSA-f6qq-3m3h-4g42
Gogithub.com/go-pkgz/auth/v22.1.2GO-2026-5348

Affected products (as reported)

VendorProductVersions
go-pkgz auth >= 1.18.0, < 1.25.2>= 2.0.0, < 2.1.2

Weakness: CWE-287 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

References