Pocket ID: OAuth redirect_uri validation bypass via userinfo/host confusion in github.com/pocket-id/pocket-id/backend

Open Source Vulnerabilities CVE-2026-28512

Pocket ID is an OIDC provider that allows users to authenticate with their passkeys to your services. From 2.0.0 to before 2.4.0, a flaw in callback URL validation allowed crafted redirect_uri values containing URL userinfo (@) to bypass legitimate callback pattern checks. If an attacker can trick a user into opening a malicious authorization link, the authorization code may be redirected to an attacker-controlled host. This vulnerability is fixed in 2.4.0.

Open Source Vulnerabilities GHSA-9h33-g3ww-mqff

### Impact A flaw in callback URL validation allowed crafted `redirect_uri` values containing URL userinfo (`@`) to bypass legitimate callback pattern checks. If an attacker can trick a user into opening a malicious authorization link, the authorization code may be redirected to an attacker-controlled host. ### Patches Fixed in `v2.3.1` (commit 3a339e33191c31b68bf57db907f800d9de5ffbc8). The fix replaces delimiter-based callback matching with structured URL pattern matching and updates validation logic/tests. ### Workarounds - Reject callback URLs containing userinfo (`@`) at reverse proxy / app policy level if feasible.

Open Source Vulnerabilities GO-2026-4653

Pocket ID: OAuth redirect_uri validation bypass via userinfo/host confusion in github.com/pocket-id/pocket-id/backend