CVE-2026-112085
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.
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
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 High
CVSS: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 High
CVSS: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 High
CVSS: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 High
CVSS: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 High
CVSS: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
| Package | Affected | Fixed |
|---|---|---|
python-tensorboardAzure Linux:3 |
through 2.16.2-6 | None known |
node-webpackUbuntu:18.04:LTS |
All versions, plus listed versions 3.5.6-1build33.5.6-1build43.5.6-2 |
None known |
node-webpackUbuntu:20.04:LTS |
All versions, plus listed versions 4.7.0-34.30.0-74.30.0-9 |
None known |
node-webpackUbuntu:22.04:LTS |
All versions, plus listed versions 4.43.0-6build44.43.0-7 |
None known |
node-webpackUbuntu:24.04:LTS |
All versions, plus listed versions 5.76.1+dfsg1+~cs17.16.16-1 |
None known |
node-webpackUbuntu: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-webpackUbuntu: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-bugopenSUSE:Tumbleweed From an advisory covering 13 CVEs |
before 0.11.0-3.1 | 0.11.0-3.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, facts | ||
| first indexed | CVE 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
github.com/webpack/webpack-dev-server/security/advisories/GHSA-cfqc-fj3v-j925
cna.openjsf.org/security-advisories.html
nvd.nist.gov/vuln/detail/CVE-2026-112085
github.com/CVEProject/cvelistV5/tree/main/cves/2026/112xxx/CVE-2026-112085.json
ubuntu.com/security/CVE-2026-112085
cve.org/CVERecord?id=CVE-2026-112085
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