Is CVE-2026-43938 actively exploited?

No active exploitation of CVE-2026-43938 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-43938 be exploited remotely?

Yes. CVE-2026-43938 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2026-43938?

CVE-2026-43938 has a CVSS score of 8.1 (HIGH).

HOME VULNERABILITIESCVE-2026-43938

HIGH

CVE-2026-43938

CWE-79Published: May 12, 2026· Updated: May 13, 2026

8.1

CVSS v3.1

EPSS:0.03%probability of exploitation in 30 daysPercentile:9.6th

Official 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.

NVD Source

Technical Analysis

CVE-2026-43938 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

Exploitation does not require any privileges, though user interaction (Required) is needed, which slightly reduces the risk of mass automated attacks.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), with a CVSS base score of 8.1.

From a weakness classification perspective (CWE-79): Cross-site scripting (XSS) vulnerabilities allow attackers to inject malicious scripts into web pages viewed by other users.