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Fencer Vulns
high 7.5

CVE-2018-14732 json

Missing Origin Validation in webpack-dev-server

published 2018-09-21 8 y ago modified 2026-06-17 4 mo ago also GHSA-cf66-xwfp-gvc4 , EUVD-2019-0183

cvss
7.5
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.5%
EPSS 2.5% chance of exploitation in 30 days, percentile 84%
public exploits
0
none known

Summary

An issue was discovered in lib/Server.js in webpack-dev-server before 3.1.6. Attackers are able to steal developer's code because the origin of requests is not checked by the WebSocket server, which is used for HMR (Hot Module Replacement). Anyone can receive the HMR message sent by the WebSocket server via a ws://127.0.0.1:8080/ connection from any origin.

Patch / fix

  • npm webpack-dev-server 3.1.11
  • webpack.js webpack-dev-server 3.1.6

Exploit prediction

2.49% chance of exploitation in the next 30 days, higher than 84% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/webpack/webpack-dev-server/issues/1445 referenced PoC, tagged "exploit" by a source, unverified
  • blog.cal1.cn https://blog.cal1.cn/post/Sniffing%20Codes%20in%20Hot%20Module%20Reloading%20Messages referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.0 7.5 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:P/I:N/A:N
GitHub 3.0 7.5 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected packages

ecosystem package affected fixed in
npm webpack-dev-server
<3.1.11
3.1.11

Classification

Weakness
  • CWE-20 Improper Input Validation

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.