fkie_cve-2026-54072

Authorizer is an open-source, self-hostable authentication and authorization server. Prior to version 2.2.1, the `/authorize` endpoint accepts any `redirect_uri` without validating it against `AllowedOrigins`. When `response_type=token` or `response_type=id_token`, the server appends `access_token`, `id_token`, and `refresh_token` as query parameters and issues a 302 redirect to the attacker-supplied URL. An unauthenticated attacker can obtain the required `client_id` from the public `/graphql?query={meta{client_id}}` endpoint. A partial fix was applied in v2.0.1 to other handlers (`oauth_login`, `verify_email`, `magic_link_login`, `forgot_password`, `invite_members`, `oauth_callback`) but `/authorize` was not included. Version 2.2.1 contains a more complete fix.

GHSA-h29v-hj44-q8cv — Authorizer: Unvalidated redirect_uri in /authorize leaks OAuth2 tokens to attacker-controlled URL

Affected: Go: github.com/authorizerdev/authorizer

## Summary

The `/authorize` endpoint accepts any `redirect_uri` without validating it against `AllowedOrigins`. When `response_type=token` or `response_type=id_token`, the server appends `access_token`, `id_token`, and `refresh_token` as query parameters and issues a 302 redirect to the attacker-supplied URL. An unauthenticated attacker can obtain the required `client_id` from the public `/graphql?query={meta{client_id}}` endpoint.

Partial fix was applied in v2.0.1 to other handlers (`oauth_login`, `verify_email`, `magic_link_login`, `forgot_password`, `invite_members`, `oauth_callback`) but `/authorize` was not included.

## Vulnerable Code

`internal/http_handlers/authorize.go`:

```go redirectURI := strings.TrimSpace(gc.Query("redirect_uri")) // ... no IsValidOrigin() call ... // response_type=token path (line ~263): if strings.Contains(redirectURI, "?") { redirectURI = redirectURI + "&" + params } else { redirectURI = redirectURI + "?" + params } handleResponse(gc, responseMode, authURL, redirectURI, ...) // 302 to attacker URL ```

Compare with the fixed `oauth_login.go` in v2.0.1 which calls `validators.IsValidOrigin(redirectURI, h.Config.AllowedOrigins)`.

## Steps to Reproduce

```bash # 1. Obtain client_id (no authentication required) CLIENT_ID=$(curl -s http://TARGET/graphql \ -H "Content-Type: application/json" \ -d '{"query":"{meta{client_id}}"}' | python3 -c "import sys,json; print(json.load(sys.stdin)['data']['meta']['client_id'])")

echo "client_…

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fkie_cve-2026-54072

GHSA-h29v-hj44-q8cv — Authorizer: Unvalidated redirect_uri in /authorize leaks OAuth2 tokens to attacker-controlled URL