Auth bypass in Go-Pkgz Auth

CVE-2026-42560

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.

Vulnerability class: Broken Authentication

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.

EPSS exploit prediction

EPSS: 0.006 (45.7th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 46th percentile — 45.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-42560: held from 0.004 to 0.006.

EPSS over last 30 days · oldest: 0.004 · newest: 0.006 · change: +0.002

Affected products

  • Go-Pkgz Auth — versions >= 1.18.0, < 1.25.2, >= 2.0.0, < 2.1.2

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-42560?
CVE-2026-42560 is a critical-severity vulnerability in Go-Pkgz Auth, classified under Improper Authentication. CVSS score: 9.1/10. Published 2026-05-09.
How severe is CVE-2026-42560?
Critical severity. CVSS v3 base score is 9.1 out of 10.