CVE-2021-3647: Open Redirect in medialize/URI.js

First published: Fri Jul 16 2021(Updated: )

### Impact If using affected versions to determine a URL's hostname, the hostname can be spoofed by using a combination of backslash (`\`) and slash (`/`) characters 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 1.19.7 is patched against all known payload variants. ### References https://github.com/medialize/URI.js/releases/tag/v1.19.7 (fix for this particular bypass) https://github.com/medialize/URI.js/releases/tag/v1.19.6 (fix for related 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 [ready-research](https://github.com/ready-research) via https://huntr.dev/

Credit: security@huntr.dev

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• collector/github-advisory-latest
• alias/GHSA-89gv-h8wf-cg8r
• alias/CVE-2021-3647
• collector/github-advisory
• collector/nvd-index
• agent/references
• agent/type
• agent/softwarecombine
• collector/mitre-cve
• source/MITRE
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• agent/event
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• collector/ibm-support
• source/IBM
• package-manager/npm
• vendor/uri.js project
• canonical/uri.js project uri.js