GHSA-rfq3-w54c-f9q5MediumCVSS 5.5

OAuth2 Redirect URL validity does not respect query parameters and character casing for loopback addresses

Published
May 24, 2021
Last Modified
February 1, 2023

🔗 CVE IDs covered (1)

📋 Description

Impact

fosite#400 (released as v0.30.2) introduced a new feature for handling redirect URLs pointing to loopback interfaces (rfc8252#section-7.3). As part of that change new behavior was introduced which failed to respect the redirect URL's (only for loopback interfaces!) query parameters

  1. Registering a client with allowed redirect URL http://127.0.0.1/callback
  2. Performing OAuth2 flow and requesting redirect URL http://127.0.0.1/callback?bar=foo
  3. Instead of an error, the browser is redirected to http://127.0.0.1/callback?bar=foo with a potentially successful OAuth2 response.

as well as the host parameter (as long as the host is a loopback interface):

  1. Registering a client with allowed redirect URL https://example.com/callback
  2. Performing OAuth2 flow and requesting redirect URL http://127.0.0.1/callback
  3. Instead of an error, the browser is redirected to http://127.0.0.1/callback with a potentially successful OAuth2 response.

These bugs are only applicable in scenarios where the attacker has control over the loopback interface (localhost, 127.0.0.1, [::1]) where the browser performing the OAuth2 flow is running.

🎯 Affected products1

  • go/github.com/ory/fosite:>= 0.30.3, < 0.34.1

🔗 References (5)