TI-2026-21629 Aliases CVE-2026-27192 GHSA-mp4x-c34x-wv3x

Feathers has an origin validation bypass via prefix matching

LOW 35CWE-346Published 2026-02-21 · Updated 2026-02-23

Key facts

Attack vector: Network
Privileges required: None
User interaction: Passive
Attack complexity: High
Attack requirements: None
Impact type: Security bypass
Confidentiality · integrity · availability: High · High · None
Fix status: Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub. Impact type from CWE-346.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.0027 19th percentileScored 2026-11-07

Fix Fixed feathers (feathersjs): 5.0.40@feathersjs/authentication-oauth (npm): 5.0.40

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
feathersjs	feathers	before 5.0.40	5.0.40	Patch available	CNA
—	@feathersjs/authentication-oauth (npm)	before 5.0.40	5.0.40	Patch available	GHSA-mp4x-c34x-wv3x

feathers Vendorfeathersjs Affected before 5.0.40 Fixed in 5.0.40 Patch available CNA
@feathersjs/authentication-oauth (npm) Vendor— Affected before 5.0.40 Fixed in 5.0.40 Patch available GHSA-mp4x-c34x-wv3x

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:feathersjs:feathers::::::node.js::*	before 5.0.40	Vulnerable	feathersjs

cpe:2.3:a:feathersjs:feathers:*:*:*:*:*:node.js:*:* Versions before 5.0.40 Vulnerable ·feathersjs

Remediation

Fix · CNA feathers (feathersjs) Fixed in 5.0.40
Fix · GHSA-mp4x-c34x-wv3x @feathersjs/authentication-oauth (npm) Fixed in 5.0.40 Advisory →

Timeline

2026-10-02 Threatist record created from CVE-2026-27192
2026-10-03 Alias added: GHSA-mp4x-c34x-wv3x

References

Patch 1

https://github.com/feathersjs/feathers/commit/ee19a0ae9bc2ebf23b1fe598a1f7361981b65401

Advisory 2

Other 2

TI-2023-19332 feathersjs socket handler allows abusing implicit toString CVSS 3.1HIGH 7.5
TI-2026-23379 NoSQL Injection via WebSocket id Parameter in MongoDB Adapter CVSS 4.0CRITICAL 9.3
TI-2026-23378 Feathersjs has an OAuth Callback Account Takeover CVSS 4.0CRITICAL 9.3
TI-2026-21630 Feathers exposes internal headers via unencrypted session cookie CVSS 4.0HIGH 8.2
TI-2026-21628 Feathers: Open Redirect in OAuth callback enables account takeover CVSS 4.0HIGH 7.4

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences