high7.3
CVE-2026-43939
YAFNET has Stored XSS in Forum Thread Posts/Replies that Allows Arbitrary JavaScript Execution for All Thread Viewers
Impact
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.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| nuget | YAFNET.Core | >= 4.0.0-beta01, <= 4.0.4 | 4.0.5 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-8rq5-wwpp-fmj2
- https://github.com/YAFNET/YAFNET/security/advisories/GHSA-8rq5-wwpp-fmj2
- https://github.com/YAFNET/YAFNET/releases/tag/v3.2.12
- https://github.com/YAFNET/YAFNET/releases/tag/v4.0.5
- https://nvd.nist.gov/vuln/detail/CVE-2026-43939