CVE-2021-3647: Open Redirect in medialize/URI.js
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, including web browsers and Node's built-in URL class.
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 (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 via https://huntr.dev/
Other sources
Medialize URI.js for Node.js could allow a remote attacker to conduct phishing attacks, caused by an open redirect vulnerability. An attacker could exploit this vulnerability using a specially-crafted URL to redirect a victim to arbitrary Web sites.
URI.js is vulnerable to URL Redirection to Untrusted Site
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
npm/urijsto a version that resolves this vulnerability.Fixed in 1.19.7 - Upgrade
Upgrade
medialize/URI.jsto a version that resolves this vulnerability.Fixed in 1.19.7
Event History
Frequently Asked Questions
What is CVE-2021-3647?
CVE-2021-3647 is a vulnerability in URI.js that allows for URL redirection to an untrusted site.
How does CVE-2021-3647 impact the affected software?
CVE-2021-3647 allows the hostname in a URL to be spoofed, which can lead to incorrect security decisions.
What is the severity of CVE-2021-3647?
CVE-2021-3647 has a severity rating of high with a CVSS score of 7.4.
How can I fix CVE-2021-3647?
To fix CVE-2021-3647, upgrade to URI.js version 1.19.7 or newer.
Where can I find more information about CVE-2021-3647?
You can find more information about CVE-2021-3647 in the following references: [GitHub Advisory](https://github.com/medialize/URI.js/security/advisories/GHSA-89gv-h8wf-cg8r), [GitHub Pull Request](https://github.com/medialize/URI.js/pull/233), [GitHub Release](https://github.com/medialize/URI.js/releases/tag/v1.19.3).