CVEvulnerability

CVE-2026-43938

8.1 HIGH Published 2026-05-12 Modified 2026-06-17 Official page ↗
Status
Deferred
Published
2026-05-12
Last modified
2026-06-17
Assigner
[email protected]
CVSS 3.1 ([email protected])
8.1 HIGH — CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
Weaknesses
CWE-116, CWE-79, CWE-80

Description

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.

Related

Weakness · CWE (3)

  • CWE-116 Improper Encoding or Escaping of Output weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation weakness
  • CWE-80 Improper Neutralization of Script-Related HTML Tags in a Web Page weakness

References