critical9.3
CVE-2026-29792
Feathers has an OAuth Callback Account Takeover issue
Impact
An unauthenticated attacker can send a crafted GET request directly to `/oauth/:provider/callback` with a forged profile in the query string. The OAuth service's authentication payload has a fallback chain that reaches params.query (the raw request query) when Grant's session/state responses are empty. Since the attacker never initiated an OAuth authorize flow, Grant has no session to work with and produces no response, so the fallback fires. The forged profile then drives entity lookup and JWT minting. The attacker gets a valid access token for an existing user without ever contacting the OAuth provider. Critical (CVSS 9.8)
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| npm | @feathersjs/authentication-oauth | >= 5.0.0, <= 5.0.41 | 5.0.42 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Feathersjs | Feathers | from 5.0.0 before 5.0.42 |