Executive brief
Budibase, an open-source low-code development platform, contains a vulnerability that allows users with 'builder' permissions to read sensitive files from the underlying server. By uploading a specially crafted ZIP file containing symbolic links, an attacker can trick the system into exposing internal configuration files, passwords, and encryption keys. This could lead to a full takeover of the Budibase instance, including access to other users' data and administrative control.
Technical details
A path traversal and symlink following vulnerability exists in the `POST /api/pwa/process-zip` endpoint of Budibase. The application uses `extract-zip@2.0.1` to unpack user-provided archives, which preserves absolute symlink targets. The icon-source validator fails to properly verify if a file is a symbolic link before processing it; it resolves the path and checks if the target exists using `fs.existsSync`, which follows links. When the application subsequently streams the 'icon' to MinIO storage, it follows the symlink and reads the target file's contents. In default Docker deployments running as root, this allows a workspace builder to read sensitive files like `/data/.env` (containing JWT secrets and database credentials) or `/etc/shadow`, enabling privilege escalation to global admin.
Affected products
- Budibase budibase < 3.39.9
Timeline
- 2026-06-04: advisory: GitHub Security Advisory published
- 2026-06-26: disclosed: CVE published to NVD
- 2026-06-26: patched: Fix released in version 3.39.9