Feathers has an OAuth Callback Account Takeover issue
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 software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | @feathersjs/authentication-oauth | >= 5.0.0, < 5.0.42 | 5.0.42 |
References
- CVSS vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N- Weakness (CWE)
CWE-287- Platform
- npm
- Package
@feathersjs/authentication-oauth- Disclosed
- 10.03.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-wg9x-qfgw-pxhj - CC BY 4.0
Vulnerability history: @feathersjs/authentication-oauth
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 4
- First → latest
- 02.2026 03.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 1
- High 3
Disclosures per year
- 2026: 4
-
Feathers has an OAuth Callback Account Takeover issue this entry
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