CVE-2026-27192 Feathers has an origin validation bypass via prefix matching
Attackers can bypass origin validation via prefix matching to exfiltrate OAuth tokens and achieve account takeover in FeathersJS applications.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-27192?
CVE-2026-27192 is a high-severity vulnerability in feathersjs feathers, published on 21 Feb 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
Feathersjs is a framework for creating web APIs and real-time applications with TypeScript or JavaScript. In versions 5.0.39 and below, 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, and 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. This issue has bee fixed in version 5.0.40.
Weakness: CWE-346
Which versions are affected by CVE-2026-27192?
2 open source packages ship an affected version, including @feathersjs/authentication-oauth. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
@feathersjs/authentication-oauth npm | All versions | 5.0.40 |
@feathersjs/authentication-oauth npm | All versions | 5.0.40 |
Products include Feathersjs Feathers.
How do I fix CVE-2026-27192?
Upgrade @feathersjs/authentication-oauth to 5.0.40 or later.
Is CVE-2026-27192 being exploited?
There is no known exploitation of CVE-2026-27192 in the wild and no public exploit code.
Other vulnerabilities in feathersjs feathers
- CVE-2026-29792 Feathersjs has an OAuth Callback Account Takeover
- CVE-2026-29793 NoSQL Injection via WebSocket id Parameter in MongoDB Adapter
- CVE-2026-27193 Feathers exposes internal headers via unencrypted session cookie
- CVE-2023-37899 feathersjs socket handler allows abusing implicit toString
- CVE-2026-27191 Feathers: Open Redirect in OAuth callback enables account takeover
Sources
Also known as GHSA-mp4x-c34x-wv3x.