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GCVE-1988-2026-0117

Vulnerability from gna-1988 – Published: 2026-09-07 13:20 – Updated: 2026-09-11 11:50
VLAI
Title
Security advisory: Pre-authentication SYSTEM RCE in iMonnit Express 4.0.5.5 (Monnit / iMonnit)
Summary
0day Rubbish Research Team is publicly disclosing a vulnerability in iMonnit Express 4.0.5.5 (Monnit / iMonnit). The research is published and a proof-of-concept is available. Pre-authentication SYSTEM RCE (CVSS 9.8, pre-authentication) iMonnit Express 4.0.5.5 is an ASP.NET Core application running as a Windows service with LocalSystem privileges, with no global [Authorize] filter. Three flaws combine into a fully unauthenticated root RCE chain: an auth bypass (an empty security answer list issues a valid admin cookie), a path-traversal file write in the certificate upload endpoint (reachable with the forged cookie), and a plugin loader that calls Assembly.Load + Activator.CreateInstance on the plugin's parameterless constructor BEFORE the IExpressPlugin check - the constructor runs as LocalSystem. Dynamically verified: whoami = nt authority\system. Impact: Full read of the host filesystem and configuration as NT AUTHORITY\SYSTEM, arbitrary OS command execution, and full control of the iMonnit Express host. Advisory: https://0day-rubbish.com/blog/imonnit-express-unauth-plugin-rce PoC and full analysis: https://github.com/Exploit-Garbage/0day-Rubbish -- 0day Rubbish Research Team https://0day-rubbish.com _______________________________________________ Sent through the Full Disclosure mailing list https://nmap.org/mailman/listinfo/fulldisclosure Web Archives & RSS: https://seclists.org/fulldisclosure/
Severity
No CVSS data available.
Impacted products
Vendor Product Version CPE status
Security advisory Pre-authentication Affected: unknown
guessed Create a notification for this product.

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