Bug 2476411 (CVE-2026-6402)

Summary:	CVE-2026-6402 webpack-dev-server: webpack-dev-server: Information disclosure due to cross-origin source code exposure
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	aazores, abarbaro, abrianik, alcohan, alizardo, anpicker, ataylor, bbrownin, bdettelb, brasmith, caswilli, cdrage, cmah, cochase, dbruscin, dhanak, dkeler, doconnor, dranck, drosa, dschmidt, dymurray, eaguilar, ebaron, ehugonne, erezende, ewittman, fdeutsch, fmariani, ggrzybek, gmalinko, gparvin, hasun, ibek, ibolton, janstey, jbalunas, jchui, jfula, jhe, jkoehler, jlanda, jmatthew, jmontleo, jolong, jowilson, jraez, jrokos, jwong, jwon, kaycoth, kshier, ktsao, kvanderr, lchilton, lphiri, mcarlett, mnovotny, nboldt, nipatil, nyancey, oaljalju, omaciel, ometelka, oramraz, pahickey, pantinor, parichar, pdelbell, pgaikwad, pjindal, psrna, ptisnovs, rhaigner, rhel-process-autobot, rjohnson, rkubis, rstepani, rushinde, sausingh, sfeifer, simaishi, slucidi, smcdonal, smullick, sseago, stcannon, stirabos, suppawar, syedriko, tasato, tcunning, teagle, thason, ttakamiy, watson-tool-maintainers, xdharmai, yfang, yguenane
Target Milestone:	---	Keywords:	Security
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Hardware:	All
OS:	Linux
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Doc Text:	A flaw was found in webpack-dev-server. When the development server operates over plain HTTP, a remote attacker can exploit a cross-origin source code exposure vulnerability. This allows a malicious website, visited by a developer, to load the bundled application source code as a script and read it across origins. Consequently, this could lead to the disclosure of sensitive application source code.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-05-12 09:01:20 UTC

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: same-origin on responses.