CVE-2026-43939
High
Description
YetAnotherForum.NET (YAF.NET) is a C# ASP.NET forum. Prior to 4.0.5 and 3.2.12, the thread posting and reply feature accepts user-supplied content via a a post or reply that is stored server-side and later rendered back into the thread page without adequate HTML sanitization or contextual output encoding. This vulnerability is fixed in 4.0.5 and 3.2.12.
SeverityHigh
CVSS7.3
Exploit probability—
ProductYafnet.core
PublishedMay 12, 2026
First seenMay 12, 2026
How to fix
Update
- YAFNET.Core4.0.5, 3.2.12 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| YAFNET.CoreNuGet | 4.0.0-beta01 ≤ v < 4.0.5, v < 3.2.12 | 4.0.5, 3.2.12 |
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