In oauth2-server (aka node-oauth2-server) through 3.1.1, the value of the redirect_uri parameter received during the authorization and token request is checked against an incorrect URI pattern ("[a-zA-Z][a-zA-Z0-9+.-]+:") before making a redirection. This allows a malicious client to pass an XSS payload through the redirect_uri parameter while making an authorization request. NOTE: this vulnerability is similar to CVE-2020-7741.
The web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect.
| Link | Tags |
|---|---|
| https://github.com/oauthjs/node-oauth2-server/issues/637 | third party advisory issue tracking |
| https://github.com/oauthjs/node-oauth2-server/blob/91d2cbe70a0eddc53d72def96864e2de0fd41703/lib/validator/is.js#L12 | third party advisory exploit |
| https://github.com/oauthjs/node-oauth2-server/blob/91d2cbe70a0eddc53d72def96864e2de0fd41703/lib/grant-types/authorization-code-grant-type.js#L143 | third party advisory exploit |
| https://tools.ietf.org/html/rfc3986#section-3 | third party advisory |
| https://tools.ietf.org/html/rfc6749#section-3.1.2 | third party advisory |