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Fencer Intel
medium 5.7

CVE-2026-49993 json

@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)

published 5mo ago modified 2mo ago also EUVD-2026-36421 , GHSA-x6qj-4h56-5rj5

cvss
5.7
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 20%
public exploits
0
none known

Summary

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.

Patch / fix

  • npm @nuxt/webpack-builder 3.21.7, 4.4.7
  • npm @nuxt/rspack-builder 3.21.7, 4.4.7
  • nuxt nuxt/rspack-builder 3.21.7, 4.4.7
  • nuxt nuxt/webpack-builder 3.21.7, 4.4.7

Is CVE-2026-49993 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
4mo ago

Exploit prediction

0.28% chance of exploitation in the next 30 days, higher than 20% of all scored CVEs (FIRST EPSS, 2026-11-11).

Exploits and checks

  • github.com https://github.com/nuxt/nuxt/security/advisories/GHSA-x6qj-4h56-5rj5 referenced PoC, tagged "exploit" by a source, unverified
  • github.com https://github.com/nuxt/nuxt/security/advisories/GHSA-6m52-m754-pw2g referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 5.9 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
CNA 4.0 5.9 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 5.7 CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

Affected packages

ecosystem package affected fixed in
npm @nuxt/webpack-builder
>=4.0.0, <4.4.7
>=3.15.4, <3.21.7
4.4.7
3.21.7
npm @nuxt/rspack-builder
>=4.0.0, <4.4.7
>=3.15.4, <3.21.7
4.4.7
3.21.7

Affected products

  • nuxt nuxt

Classification

Weakness
  • CWE-749 Exposed Dangerous Method or Function

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of nuxt/nuxt published their own advisory on GitHub. Reviewed sources take precedence over it.