fast-uri before 4.1.2, 3.1.5, and 2.4.4 requires a literal double forward slash to recognize a URI authority, so a reference that uses a backslash based introducer in place of it (backslash backslash, forward slash backslash, or backslash forward slash) is parsed with no authority and folds into the path. Nodes native WHATWG URL parser instead treats a backslash as interchangeable with a forward slash for special schemes, so the two parsers extract different hosts from the same input. Applications that use fast-uri to enforce host based policy such as allowlists, SSRF filtering, or redirect validation before passing the same URL into Nodes URL or fetch consumers can be steered to an unintended host. Upgrade to fast-uri 4.1.2, 3.1.5, or 2.4.4.
Weakness
Product A handles inputs or steps differently than Product B, which causes A to perform incorrect actions based on its perception of B’s state.
Related Attack Patterns
- https://cwe.mitre.org/data/definitions/105.html
- https://cwe.mitre.org/data/definitions/273.html
- https://cwe.mitre.org/data/definitions/34.html