GitHub Advisoryadvisory · npm
GHSA-mp4x-c34x-wv3x Feathers has an origin validation bypass via prefix matching
HIGH
Official page ↗
- Aliases
- CVE-2026-27192
- Ecosystem
- npm
- Packages
- @feathersjs/authentication-oauth
- Severity
- High
- CVSS vector
- CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
- Weaknesses
- CWE-346
- Reviewed
- 2026-02-19
Affected packages
• npm @feathersjs/authentication-oauth: < 5.0.40 → fixed in 5.0.40
Description
The origin validation uses `startsWith()` for comparison, allowing attackers to bypass the check by registering a domain that shares a common prefix with an allowed origin.
The `getAllowedOrigin()` function checks if the Referer header starts with any allowed origin:
```javascript
// https://github.com/feathersjs/feathers/blob/dove/packages/authentication-oauth/src/strategy.ts#L75
const allowedOrigin = origins.find((current) => referer.toLowerCase().startsWith(current.toLowerCase()));
```
This comparison is insufficient as it only validates the prefix. This is exploitable when the `origins` array is configured and an attacker registers a domain starting with an allowed origin string (e.g., `https://target.com.attacker.com` bypasses `https://target.com`).
On its own, tokens are still redirected to a configured origin. However, in specific scenarios an attacker can initiate the OAuth flow from an unauthorized origin and exfiltrate tokens, achieving full account takeover.
Credits: Abdelwahed Madani Yousfi (@vvxhid) / Edoardo Geraci (@b0-n0-b0) / Thomas Rinsma (@ThomasRinsma) From Codean Labs.
Related
Alias · CVE (1)
- CVE-2026-27192 Feathersjs is a framework for creating web APIs and real-time applications with TypeScript or JavaScript. vulnerability
Weakness · CWE (1)
- CWE-346 Origin Validation Error weakness
References
- https://github.com/feathersjs/feathers/security/advisories/GHSA-mp4x-c34x-wv3x web
- https://nvd.nist.gov/vuln/detail/CVE-2026-27192 advisory
- https://github.com/feathersjs/feathers/commit/ee19a0ae9bc2ebf23b1fe598a1f7361981b65401 web
- https://github.com/feathersjs/feathers package
- https://github.com/feathersjs/feathers/releases/tag/v5.0.40 web