CVE-2026-6402Patch(webpack.js / webpack-dev-server)

LOWCVSS 6.5 · MEDIUM

Signal is active with 1 mentions in latest observed window

Immediate actions

  • Patch webpack.js webpack-dev-server systems immediately

Recommended action window: Monitor and triage in normal cycle

NVD description

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.

0.5/ 10 priority

Sources & remediation

Weakness type (CWE)
CWE-749

Priority

LOW

Exploitation

NONE

PoC

NONE

Patch

AVAILABLE

Momentum

NONE

Are you affected?

If you run products in this scope, you should treat this CVE as relevant to your environment.

  • webpack-dev-server

Threat summary

  • Patch or workaround signal is available
  • 1 mentions across 1 observed day

What's happening

  • Patch or workaround mentioned in 1 signal
  • Technical details provided in 1 signal
  • 1 total mentions across 1 day

Affected systems

Vendors
Products
webpack-dev-server

Deep dive

Activity timeline1 mentions / 1d
00111Mentions · 2026-05-12: 1Patch / Workaround · 2026-05-12: 1Technical Details · 2026-05-12: 105-12
Signal classification1 categories
Patch
1100.0%
Referenced assets1 URL
Full discourse1 post
  • Ulises Gascón@kom_256
    Patch

    🚨 Medium-severity security fix in webpack-dev-server@5.2.4 just released! Patches CVE-2026-6402 — webpack-dev-server vulnerable to cross-origin source code exposure on non-HTTPS origins https://github.com/webpack/webpack-dev-server/security/advisories/GHSA-79cf-xcqc-c78w

    Post summary

    A patch for webpack‑dev‑server 5.2.4 has been released to remediate CVE‑2026‑6402, which exposes source code in cross‑origin requests over non-HTTPS origins.

    01010149
    5.5K followersView on X
CPE platform detail1 entries

1 of 1 entries

PartVendorProductVersionTarget SWTarget HW
Appwebpack.jswebpack-dev-server---

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