Vulnerability · Published Sep 2, 2026 · Assigned by GitHub_M
CVE-2026-84452Windows ML CLI: CORS misconfig enables localhost RCE
High 8.6
In plain English
A high-severity missing authentication in winml-cli from microsoft. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 1.6% (higher than 76% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Windows ML CLI is a command line tool for building portable, performant, and high-quality AI models for Windows ML. Prior to 0.4.0, the src/winml/modelkit/serve/cli_api.py component exposes WinML CLI commands through a localhost HTTP API without authentication and configures the allow_origins setting as a wildcard in both src/winml/modelkit/serve/cli_api.py and src/winml/modelkit/serve/app.py. A malicious website loaded by a user can send cross-origin requests to /v1/cli/build or /v1/cli/config and set the trust_remote_code parameter to true, which is converted to the --trust-remote-code command-line flag without validation. This reaches AutoConfig.from_pretrained with trust_remote_code=True in src/winml/modelkit/loader/_autoconfig.py and imports Python code from an attacker-controlled model repository, resulting in arbitrary code execution as the server user. This issue is fixed in version 0.4.0.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| PyPI | winml-cli | 0.4.0 | GHSA-96p9-rh4f-92cf |
| PyPI | winml-cli | 0.4.0 | PYSEC-2026-3944 |
Affected products (as reported)
Weakness: CWE-942, CWE-306 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
References
- https://github.com/microsoft/winml-cli/security/advisories/GHSA-96p9-rh4f-92cf x_refsource_CONFIRM
- https://github.com/microsoft/winml-cli/pull/1321 x_refsource_MISC
- https://github.com/microsoft/winml-cli/commit/f4073e0ef4700a25b623487e7e45c421ca0b9993 x_refsource_MISC