Vulnerability CVE-2020-26938
Published: 2022-08-29

Description:
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.

 References:
https://github.com/oauthjs/node-oauth2-server/issues/637
https://github.com/oauthjs/node-oauth2-server/blob/91d2cbe70a0eddc53d72def96864e2de0fd41703/lib/validator/is.js#L12
https://tools.ietf.org/html/rfc6749#section-3.1.2
https://tools.ietf.org/html/rfc3986#section-3
https://github.com/oauthjs/node-oauth2-server/blob/91d2cbe70a0eddc53d72def96864e2de0fd41703/lib/grant-types/authorization-code-grant-type.js#L143
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