A publicly disclosed vulnerability in vMix 29 (29.0.0.48) allows pre-authentication remote code execution through the product’s Web Controller on port 8088. The flaw is exposed via the GET /api/?Function=ScriptStartDynamic&Value=<VB.NET source> endpoint, which compiles and runs attacker-supplied VB.NET code using VBScriptProvider.Compile. Although vMix attempts to prevent abuse with a six-item substring blocklist, researchers showed the generated compilation template includes Imports System.Diagnostics, enabling attackers to reach Process.Start without using blocked terms and bypass the intended restrictions.
The issue is especially severe because the Web Controller defaults to a blank password, and vendor documentation indicates that a blank password means no login is required regardless of access settings, leaving the API reachable without authentication. Successful exploitation can deliver arbitrary OS command execution and arbitrary file read/write with the privileges of vMix64.exe, which is commonly run as an administrator account. The advisory rates the flaw CVSS 9.8 and describes it as a critical exposure in a product that had not previously been assigned public CVEs.

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The same vMix 29 remote code execution advisory was subsequently distributed through the Full Disclosure mailing list. The posting reiterated that the flaw allowed unauthenticated arbitrary OS command execution and file read/write through the ScriptStartDynamic endpoint.
0day Rubbish Research Team publicly disclosed a pre-authentication remote code execution vulnerability affecting Studio Coast Pty Ltd's vMix 29 version 29.0.0.48. The advisory described unauthenticated exploitation via the Web Controller API, rated the issue CVSS 9.8, and made a proof of concept publicly available.
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