GCVE-1988-2026-0117
Vulnerability from gna-1988 – Published: 2026-09-07 13:20 – Updated: 2026-09-11 11:50
VLAI
EPSS
VEX
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.
Assigner
References
7 references
Impacted products
1 product
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Security | advisory Pre-authentication |
Affected:
unknown
|
guessed |
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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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