CVE-2020-15233
OAuth2 Redirect URL validity does not respect query parameters and character casing for loopback addresses
Impact
### Impact [fosite#400](https://github.com/ory/fosite/pull/400) (released as v0.30.2) introduced a new feature for handling redirect URLs pointing to loopback interfaces ([rfc8252#section-7.3](https://tools.ietf.org/html/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 packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| go | github.com/ory/fosite | >= 0.30.3, < 0.34.1 | 0.34.1 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Ory | Fosite | from 0.30.2 before 0.34.1 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/ory/fosite/commit/cdee51ebe721bfc8acca0fd0b86b030ca70867bf
- https://github.com/ory/fosite/security/advisories/GHSA-rfq3-w54c-f9q5
- https://github.com/advisories/GHSA-rfq3-w54c-f9q5
- https://nvd.nist.gov/vuln/detail/CVE-2020-15233
- https://github.com/ory/fosite/pull/400