CVE-2026-112085webpack-dev-server vulnerable to cross-origin WebSocket access via proxied upgrades
Updated under an hour ago ()
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It affects webpack-dev-server. Add what you run to find out whether that includes you.
EPSS puts the chance of exploitation in the next 30 days at 0.15%, higher than 4% of scored CVEs.
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webpack-dev-server is a development server that provides live reloading for webpack projects. In versions before 5.2.7 and in version 6.0.0, when a proxy entry is configured to forward WebSockets, the server forwards non-HMR WebSocket upgrade requests to the proxy target without validating the Host or Origin headers, so the allowedHosts protection does not apply to those proxied upgrades. A malicious web page visited by a developer can open a cross-origin WebSocket through the dev server and read from and write to the proxied backend, even when the server is bound to loopback. The issue is fixed in webpack-dev-server 5.2.7 and 6.1.0, where proxied WebSocket upgrades pass the same Host and Origin validation as the HMR WebSocket, and users should upgrade to one of those versions or later. As a workaround, omit WebSocket forwarding from proxy entries that do not need it and scope the proxy to specific paths.
- CVSS
- 8.2 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N
- Weakness (CWE)
- CWE-346, CWE-1385
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- 0.15% (percentile 4)
- Assigned by
- openjs
- NVD analysis
- Undergoing Analysis
- Record last updated
- Oct 22, 2026
- First seen by InfoSec Signals
- Oct 22, 2026
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.