## Summary The `sendPasswordResetEmail` mutation in WPGraphQL is explicitly designed to prevent user enumeration. The resolver in `src/Mutation/SendPasswordResetEmail.php` states in a code comment: `// We obsfucate the actual success of this mutation to prevent user enumeration.` The mutation always returns `success: true` regardless of whether the supplied username/email belongs to an existing user. The intended public output field is only `success: Boolean`. However, a deprecated `user` field is still registered on the `SendPasswordResetEmailPayload` output type in `src/Deprecated.php` (lines 433-450). This deprecated field resolves to a full `User` object when the supplied username/email corresponds to an existing author-class user, and `null` otherwise — completely undermining the anti-enumeration design. The `@todo remove in 3.0.0` comment acknowledges the field is scheduled for removal, but it remains active in all 2.x releases, including current 2.14.1. Discovered via source code review on May 29, 2026. ## Details The mutation resolver in `src/Mutation/SendPasswordResetEmail.php`: ```php $payload = ['success' => true, 'id' => null]; $user_data = self::get_user_data($input['username']); if (!$user_data) { graphql_debug(...); return $payload; // id stays null } // ...send email, then... return ['id' => $user_data->ID, 'success' => true]; ``` The intended public output field is only `success`. The `id` is internal-only state for downstream resolvers. `src/Deprecated.php` registers an additional `user` field on the same payload type: ```php register_graphql_field( 'SendPasswordResetEmailPayload', 'user', [ 'type' => 'User', 'deprecationReason' => static function () { return __('This field will be removed...'); }, 'resolve' => static function ($payload, $args, AppContext $context) { return !empty($payload['id']) ? $context->get_loader('user')->load_deferred($payload['id']) : null; }, ], ); ``` This field reads the internal `$payload['id']` and resolves it through the standard user loader. The User Model's `allowed_restricted_fields` policy permits unauthenticated reads of public author fields (`databaseId`, `name`, `firstName`, `lastName`, `slug`, `description`, `uri`, `url`). ## PoC ```graphql mutation EnumerateUser { sendPasswordResetEmail(input: { username: "[email protected]" }) { success user { databaseId name firstName lastName slug description uri } } } ``` Behavior: - Non-existing user/email → `data.sendPasswordResetEmail.user` is `null` - - Existing author-class user → `data.sendPasswordResetEmail.user` is a full User object with the listed fields populated - - `success` always returns `true`, preserving the appearance of obfuscation — the deprecated `user` field is the leak ## Impact 1. **Username/email enumeration:** unauthenticated attacker can verify whether any username or email is registered, with no WPGraphQL-side rate limiting 2. 2. **Profile disclosure for author-class users:** for any user with published posts (including editors and administrators), the attacker obtains `databaseId`, `name`, `firstName`, `lastName`, `slug`, `description` (user bio), `uri` — substantially more than mere existence 3. 3. **Bypasses partial hardening:** sites that disabled the REST API user endpoint, the user XML sitemap, and `?author=N` author redirects may still be vulnerable through this WPGraphQL path 4. 4. **Spearphishing setup:** firstName/lastName/description for authors provides personalized phishing material ## Recommended fix Either remove the deprecated `user` field entirely (advance the existing `@todo remove in 3.0.0`) or change the resolver to always return `null`: ```diff 'resolve' => static function ($payload, $args, AppContext $context) { - return !empty($payload['id']) ? $context->get_loader('user')->load_deferred($payload['id']) : null; - + // Always null — this deprecated field previously leaked user existence, - + // undermining the anti-enumeration design of the sendPasswordResetEmail mutation. - + return null; - }, - ``` Defense in depth — change the mutation resolver itself to not populate `$payload['id']` on real success: ```diff return [ - 'id' => $user_data->ID, - + 'id' => null, - 'success' => true, - ]; - ``` Luke Granto — independent security researcher operating in good faith. Discovery via source code review of wp-graphql/wp-graphql v2.14.1, approximately 15 minutes from `git clone` to confirmed bug. No live exploitation against any third-party deployment.

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