Your RSA-2048 keys break in 2030. Find every one of them before attackers do.
📦 npm

GHSA-mp4x-c34x-wv3x

Feathers has an origin validation bypass via prefix matching

Also known asCVE-2026-27192
Published
Feb 19, 2026
Updated
Feb 23, 2026
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed

EPSS Exploitation Probability

via FIRST.org ↗
0.2%probability of exploitation in next 30 days
Lower Risk15th percentile+0.23%
0.00%0.25%0.49%0.74%0.0%0.0%0.0%0.0%0.2%Mar 26May 26Jun 26

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

1 pkg affected

Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.

@feathersjs/authentication-oauthnpm
21Kdownloads / week

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:

// 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.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
📦npm@feathersjs/authentication-oauthall versions5.0.40

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @feathersjs/authentication-oauth. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

  2. Fix

    Update @feathersjs/authentication-oauth to 5.0.40 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-mp4x-c34x-wv3x is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 pinpoints whether GHSA-mp4x-c34x-wv3x is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-mp4x-c34x-wv3x. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

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`
O3 Security · Impact-Aware SCA

Is GHSA-mp4x-c34x-wv3x in your dependencies?

O3 detects GHSA-mp4x-c34x-wv3x across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.