GHSA-p6j9-7xhc-rhwp

### Impact If using affected versions to determine a URL's hostname, the hostname can be spoofed by using a backslash (`\`) character as part of the scheme delimiter, e.g. `scheme:/\hostname`. If the hostname is used in security decisions, the decision may be incorrect.

Depending on library usage and attacker intent, impacts may include allow/block list bypasses, SSRF attacks, open redirects, or other undesired behavior.

Example URL: `https:/\expected-example.com/path` Escaped string: `https:/\\expected-example.com/path` (JavaScript strings must escape backslash)

Affected versions incorrectly return no hostname. Patched versions correctly return `expected-example.com`. Patched versions match the behavior of other parsers which implement the [WHATWG URL specification](https://url.spec.whatwg.org/), including web browsers and [Node's built-in URL class](https://nodejs.org/api/url.html).

### Patches Version 1.19.6 is patched against all known payload variants.

### References https://github.com/medialize/URI.js/releases/tag/v1.19.6 (fix for this particular bypass) https://github.com/medialize/URI.js/releases/tag/v1.19.4 (fix for related bypass) https://github.com/medialize/URI.js/releases/tag/v1.19.3 (fix for related bypass) [PR #233](https://github.com/medialize/URI.js/pull/233) (initial fix for backslash handling)

### For more information If you have any questions or comments about this advisory, open an issue in https://github.com/medialize/URI.js

### Reporter credit [Yaniv Nizry](https://twitter.com/ynizry) from the CxSCA AppSec team at Checkmarx