Executive brief
Alf.io is an open-source ticket reservation system used for managing events like conferences and trade shows. A security flaw allows an administrator to upload a malicious script that can read any file on the server, such as database passwords, encryption keys, or customer data. This information can then be automatically sent to a server controlled by the attacker, leading to a significant data breach.
Technical details
A path traversal vulnerability exists in the Alf.io extension sandbox due to the injection of a fully-functional HTTP client (`simpleHttpClient`) into the scope of extension scripts. The `postFileAndSaveResponse()` method in this client accepts an arbitrary filesystem path as a parameter and uses `new FileInputStream(file)` without any path validation, directory restrictions, or allowlists. An authenticated attacker with administrative privileges can create a malicious JavaScript extension to read sensitive files (such as `application.properties` or SSH keys) accessible to the JVM process and exfiltrate them via an HTTP POST request to an external server. The issue is fixed in version 2.0-M5-2606.
Affected products
- alfio-event Alf.io <= 2.0-M5-2509-1
Timeline
- 2026-06-02: disclosed
- 2026-06-02: advisory
- 2026-06-02: patched: Fixed in version 2.0-M5-2606