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Security Advisories: MDE2OlNlY3VyaXR5QWR2aXNvcnlHSFNBLXJmcTMtdzU0Yy1mOXE1

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

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.

Permalink: https://github.com/advisories/GHSA-rfq3-w54c-f9q5
JSON: https://advisories.ecosyste.ms/api/v1/advisories/MDE2OlNlY3VyaXR5QWR2aXNvcnlHSFNBLXJmcTMtdzU0Yy1mOXE1
Source: GitHub Advisory Database
Origin: Unspecified
Severity: Moderate
Classification: General
Published: about 2 years ago
Updated: 4 months ago


CVSS Score: 5.5
CVSS vector: CVSS:3.0/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:N/E:P/RL:O/RC:C

Identifiers: GHSA-rfq3-w54c-f9q5, CVE-2020-15233
References:

Affected Packages

go:github.com/ory/fosite
Versions: >= 0.30.3, < 0.34.1
Fixed in: 0.34.1