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CVE-2026-112085

webpack-dev-server vulnerable to cross-origin WebSocket access via proxied upgrades

8.2 High

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.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
Required

What an attacker can affect

Confidentiality
High
Integrity
Low
Availability
None

Exploit likelihood

0.15%Unchanged since Oct 22, 2026
90%50%10%1%

What each source reports

CVE List Score used 8.2

webpack-dev-server vulnerable to cross-origin WebSocket access via proxied upgrades

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.

Record
CVE-2026-112085
CVSS 3.1
8.2 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N
Weakness
CWE-346, CWE-1385
Updated
2026-11-02
EUVDEUVD-2026-108108 8.2

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.

Record
EUVD-2026-108108
CVSS 3.1
8.2 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N
Updated
2026-11-02
NVD 8.2

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.

Record
CVE-2026-112085
CVSS 3.1
8.2 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N
Weakness
CWE-346, CWE-1385
Updated
2026-11-02
OSV 8.2

webpack-dev-server vulnerable to cross-origin WebSocket access via proxied upgrades

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.

Record
CVE-2026-112085
CVSS 3.1
8.2 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N
Weakness
CWE-1385, CWE-346
Updated
2026-11-02
OSVUBUNTU-CVE-2026-112085 8.2

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.

Record
UBUNTU-CVE-2026-112085
CVSS 3.1
8.2 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N
Updated
2026-11-02
OSVAZL-111065 No score

CVE-2026-112085 affecting package python-tensorboard 2.16.2-6

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.

Record
AZL-111065
Updated
2026-11-02
OSVopenSUSE-SU-2026:12261-1 No score

git-bug-0.11.0-3.1 on GA media

These are all security issues fixed in the git-bug-0.11.0-3.1 package on the GA media of openSUSE Tumbleweed.

Record
openSUSE-SU-2026:12261-1
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
python-tensorboard
Azure Linux:3
through 2.16.2-6 None known
node-webpack
Ubuntu:18.04:LTS
All versions, plus listed versions
3.5.6-1build33.5.6-1build43.5.6-2
None known
node-webpack
Ubuntu:20.04:LTS
All versions, plus listed versions
4.7.0-34.30.0-74.30.0-9
None known
node-webpack
Ubuntu:22.04:LTS
All versions, plus listed versions
4.43.0-6build44.43.0-7
None known
node-webpack
Ubuntu:24.04:LTS
All versions, plus listed versions
5.76.1+dfsg1+~cs17.16.16-1
None known
node-webpack
Ubuntu:26.10
All versions, plus listed versions
5.105.4+dfsg1+~cs15.13.23-25.108.0+dfsg1+~cs14.7.20-2
None known
node-webpack
Ubuntu:26.04:LTS
All versions, plus listed versions
5.97.1+dfsg1+~cs11.18.27-35.97.1+dfsg1+~cs11.18.27-45.105.4+dfsg1+~cs15.13.23-2
None known
git-bug
openSUSE:Tumbleweed
From an advisory covering 13 CVEs
before 0.11.0-3.1
0.11.0-3.1

History

History
RecordedChangedSources
affected, facts
first indexedCVE List, EUVD, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-112085 is a high vulnerability (CVSS 8.2) in Webpack-dev-server, published October 22, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.15%, the 3rd percentile. No source names a fixed version.

References

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