9.8

CVSS Score

3.0

-

CVSS Score

Basic Information

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CVE-2017-9785

CVE-2017-9785: Deserialization of Untrusted Data in NancyFX Nancy

Csrf.cs in NancyFX Nancy before 1.4.4 and 2.x before 2.0-dangermouse has Remote Code Execution via Deserialization of JSON data in a CSRF Cookie.

(GitHub Advisory)

Miggo Vulnerability Database

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CVE-2017-9785

CVE-2017-9785:

9.8

CVSS Score

3.0

-

CVSS Score

Basic Information

Technical Details

Package Name	Ecosystem	Vulnerable Versions	First Patched Version
Nancy	nuget	<= 1.4.3	1.4.4
Nancy	nuget	>= 2.0.0-alpha, <= 2.0.0-clinteastwood	2.0.0

Technical Details

Vulnerability Intelligence
Miggo AI

Root Cause Analysis

The vulnerability stemmed from JSON deserialization in CSRF cookie processing. The release notes explicitly state that the patch removed JSON (de)serialization in Csrf.cs. This indicates that:

CsrfToken.Load was responsible for deserializing cookie data using JsonConvert
CsrfApplicationStartup.Initialize would be present in any stack trace involving CSRF processing While the exact code changes aren't shown, the release notes and Nancy's architecture strongly suggest these functions were involved in the vulnerable flow. The high confidence for CsrfToken.Load comes from the direct link between JSON removal and deserialization RCE vectors.

Vulnerable functions

Only Mi**o us*rs **n s** t*is s**tion

WAF Protection Rules

WAF Rule

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Reasoning

*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.

9.8

-

Basic Information

Basic Information

Concerned about an active attack path?

CVE-2017-9785: Deserialization of Untrusted Data in NancyFX Nancy

CVE-2017-9785:

9.8

-

Basic Information

Basic Information

Technical Details

Technical Details

Vulnerability IntelligenceMiggo AI

Root Cause Analysis

Vulnerable functions

WAF Protection Rules

WAF Rule

Reasoning

Vulnerability IntelligenceMiggo AI

9.8

9.8

Basic Information

Basic Information

CVE-2017-9785: Deserialization of Untrusted Data in NancyFX Nancy

Vulnerability IntelligenceMiggo AI

Root Cause Analysis

Vulnerable functions

WAF Protection Rules

WAF Rule

Reasoning

Technical Details

Vulnerability Intelligence
Miggo AI

Vulnerability Intelligence
Miggo AI

Vulnerability Intelligence
Miggo AI