Auth bypass in Microsoft Winml-Cli

CVE-2026-84452

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.

Vulnerability class: Broken Authentication

Published · last modified .

EPSS exploit prediction

EPSS: 0.016 (75.5th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 76th percentile — 75.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-84452: rose from 0.009 to 0.016.

EPSS over last 30 days · oldest: 0.009 · newest: 0.016 · change: +0.007

Affected products

Weakness classification (CWE)

References