The vulnerability in Dify allows an authenticated user to bypass authorization checks on the file preview endpoint and read up to 3,000 characters of any uploaded document across all tenants and workspaces, exposing sensitive content without ownership or permission verification. This bypass is an information disclosure flaw under CWE-639, permitting attackers to acquire confidential data through the public API endpoint. The model of the attack, entirely reliant on a known file UUID and ordinary authentication, leaves confidential documents exposed to any user who can obtain the file identifier.

All installations of Dify by Langgenius running version 1.14.1 or earlier are affected. The issue applies to the file preview API endpoint available to all authenticated users across all tenants and workspaces, regardless of document ownership.

With a CVSS score of 8.2, the vulnerability is considered high severity. The EPSS score is < 1% (approximately 0.00036), indicating a low exploitation probability, but the vulnerability can still be exploited easily because the file preview endpoint is publicly reachable and any attacker can create a free account on Dify Cloud, allowing them to authenticate and request the preview for any intercepted or guessed file UUID. The lack of a KEV listing suggests no known mass exploitation, yet the straightforward attack path and broad access make it a significant risk for data leakage.