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Fencer Vulns
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 2026-06-12 4 mo ago modified 2026-09-10 1 mo ago also GHSA-x6qj-4h56-5rj5 , EUVD-2026-36421

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

CISA SSVC

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

Exploit prediction

0.28% chance of exploitation in the next 30 days, higher than 20% of all scored CVEs (FIRST EPSS, 2026-11-08).

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 Vulns 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.