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)

Severity: medium (CVSS 5.7 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-06-12 · updated 2026-06-17
Weakness: CWE-749

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.

Affected products

Nuxt/Rspack-Builder: from 3.15.4 before 3.21.7; from 4.0.0 before 4.4.7 — fixed in 3.21.7, 4.4.7
Nuxt/Webpack-Builder: from 3.15.4 before 3.21.7; from 4.0.0 before 4.4.7 — fixed in 3.21.7, 4.4.7

How to fix

Upgrade to a fixed version: Nuxt/Rspack-Builder 3.21.7, 4.4.7; Nuxt/Webpack-Builder 3.21.7, 4.4.7. Check the vendor advisory for mitigations.

References

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