CVE-2026-43938

Published: Mag 12, 2026 Last Modified: Mag 12, 2026
ExploitDB:
Other exploit source:
Google Dorks:
HIGH 8,1
Source: [email protected]
Attack Vector: network
Attack Complexity: low
Privileges Required: none
User Interaction: required
Scope: unchanged
Confidentiality: high
Integrity: high
Availability: none

Description

AI Translation Available

YetAnotherForum.NET (YAF.NET) is a C# ASP.NET forum. Prior to 4.0.5 and 3.2.12, the application's database logger (YAFNET.Core/Logger/DbLogger.cs) captures the incoming request's User-Agent header into a JObject, serializes it with JsonConvert, and stores the result in the EventLog.Description column whenever an event (e.g., an unhandled exception) is logged. The admin event-log page (YetAnotherForum.NET/Pages/Admin/EventLog.cshtml.cs) later deserializes that JSON in FormatStackTrace() and interpolates the UserAgent value directly into an HTML string with no encoding, and the Razor view EventLog.cshtml emits the result through @Html.Raw. This vulnerability is fixed in 4.0.5 and 3.2.12.

79

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Stable
Abstraction: Base Structure: Simple
Common Consequences
Security Scopes Affected:
Access Control Confidentiality Integrity Availability
Potential Impacts:
Bypass Protection Mechanism Read Application Data Execute Unauthorized Code Or Commands
Applicable Platforms
Technologies: AI/ML, Web Based, Web Server
Likelihood of Exploit: High
View CWE Details
80

Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)

Incomplete
Abstraction: Variant Structure: Simple
Common Consequences
Security Scopes Affected:
Confidentiality Integrity Availability
Potential Impacts:
Read Application Data Execute Unauthorized Code Or Commands
Applicable Platforms
Technologies: Web Based, Web Server
Likelihood of Exploit: High
View CWE Details
116

Improper Encoding or Escaping of Output

Draft
Abstraction: Class Structure: Simple
Common Consequences
Security Scopes Affected:
Integrity Confidentiality Availability Access Control
Potential Impacts:
Modify Application Data Execute Unauthorized Code Or Commands Bypass Protection Mechanism
Applicable Platforms
Technologies: AI/ML, Database Server, Not Technology-Specific, Web Server
Likelihood of Exploit: High
View CWE Details
https://github.com/YAFNET/YAFNET/security/advisories/GHSA-3…
https://github.com/YAFNET/YAFNET/security/advisories/GHSA-33gv-fc78-qgf5
https://github.com/YAFNET/YAFNET/security/advisories/GHSA-3…
https://github.com/YAFNET/YAFNET/security/advisories/GHSA-33gv-fc78-qgf5