Search/CVE-2026-6402
● CVE — Medium

CVE-2026-6402

Vendorwebpack.jsProductwebpack-dev-serverDiscoveredMay 12, 2026UpdatedMay 18, 2026

webpack-dev-server versions up to and including 5.2.3 are vulnerable to cross-origin source code exposure when serving over a non-potentially trustworthy origin such as plain HTTP. The previous fix relied on the Sec-Fetch-Mode and Sec-Fetch-Site request headers, which browsers omit for non-trustworthy origins, allowing a malicious site to load the bundled source as a script and read it across origins. Impact: an attacker controlling a website visited by a developer running webpack-dev-server can recover the application source code when the dev server runs over HTTP at a guessable host and port. Chromium based browsers from Chrome 142 onward are not affected due to local network access restrictions. Upgrade to webpack-dev-server 5.2.4 or later, which sets Cross-Origin-Resource-Policy:…

CVSS v3.1
5.3 MEDIUM
EPSS
0.29%
probability of exploitation in 30 days
CISA KEV
Not listed
no confirmed exploitation reported
News coverage
0
sources referencing this CVE
Related IOCs
0
seen in the same coverage
EPSS Trend
Aug 26, 2026 → Oct 26, 2026
● 0.00pp
0.29% → 0.29% over 3 tracked changes
CVSS v3.1 Detail
Attack VectorNETWORK
Attack ComplexityHIGH
Privileges RequiredNONE
User InteractionREQUIRED
ScopeUNCHANGED
ConfidentialityHIGH
IntegrityNONE
AvailabilityNONE
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N
Connections
2 relationships
Timeline
disclosure → media coverage
May 12, 2026
Disclosure — published as a CVE record. · last revised by NVD May 18, 2026