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: Go: github.com/go-pkgz/auth, Go: github.com/go-pkgz/auth/v2

### Summary 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.

### Details The bug is in the Patreon provider's user-mapping logic.

Both the root module and the `v2` module create a fresh empty `token.User{}` and then derive the Patreon ID from `userInfo.ID` before that field has been populated:

```go mapUser: func(data UserData, bdata []byte) token.User { userInfo := token.User{}

uinfoJSON := uinfo{} if err := json.Unmarshal(bdata, &uinfoJSON); err == nil { userInfo.ID = "patreon_" + token.HashID(sha1.New(), userInfo.ID) userInfo.Name = uinfoJSON.Data.Attributes.FullName userInfo.Picture = uinfoJSON.Data.Attributes.ImageURL ... } return userInfo } ```

Affected locations:

- `provider/providers.go:257` - `v2/provider/providers.go:257`

At that point, `userInfo.ID` is still the empty string, so the effective result is always:

```text patreon_ + sha1("") ```

which is:

```text patreon_da39a3ee5e6b4b0d3255bfef95601890afd80709 ```

for every Pat…