cnvd-2026-18150

EUVD-2026-275871

fkie_cve-2026-32101

StudioCMS is a server-side-rendered, Astro native, headless content management system. Prior to 0.3.1, the S3 storage manager's isAuthorized() function is declared async (returns Promise<boolean>) but is called without await in both the POST and PUT handlers. Since a Promise object is always truthy in JavaScript, !isAuthorized(type) always evaluates to false, completely bypassing the authorization check. Any authenticated user with the lowest visitor role can upload, delete, rename, and list all files in the S3 bucket. This vulnerability is fixed in 0.3.1.

GHSA-mm78-fgq8-6pgr — StudioCMS S3 Storage Manager Authorization Bypass via Missing `await` on Async Auth Check

Affected: npm: @studiocms/s3-storage

## Summary

The S3 storage manager's `isAuthorized()` function is declared `async` (returns `Promise<boolean>`) but is called without `await` in both the POST and PUT handlers. Since a Promise object is always truthy in JavaScript, `!isAuthorized(type)` always evaluates to `false`, completely bypassing the authorization check. Any authenticated user with the lowest `visitor` role can upload, delete, rename, and list all files in the S3 bucket.

## Details

The `isAuthorized` function is typed as returning `Promise<boolean>` in `packages/studiocms/src/handlers/storage-manager/definitions.ts:88`:

```typescript export type ParsedContext = { getJson: () => Promise<ContextJsonBody>; getArrayBuffer: () => Promise<ArrayBuffer>; getHeader: (name: string) => string | null; isAuthorized: (type?: AuthorizationType) => Promise<boolean>; // async }; ```

Both context drivers implement it as `async` — `packages/studiocms/src/handlers/storage-manager/core/effectify-astro-context.ts:32`:

```typescript isAuthorized: async (type) => { switch (type) { case 'headers': { // ... token verification ... const isEditor = level >= UserPermissionLevel.editor; if (!isEditor) return false; return true; } default: { const isEditor = locals.StudioCMS.security?.userPermissionLevel.isEditor || false; return isEditor; } } }, ```

But in the S3 storage manager, it's called without…

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cnvd-2026-18150

EUVD-2026-275871

fkie_cve-2026-32101

GHSA-mm78-fgq8-6pgr — StudioCMS S3 Storage Manager Authorization Bypass via Missing `await` on Async Auth Check