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Vulnerability record · CVE-2026-43939 · published 12 May 2026

CVE-2026-43939: Cross-site scripting vulnerability

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.

7.3 CVSS 3.1 High EPSS 0.35% · top 73.6% CWE-79 · Cross-site scriptingCWE-80 · CWE-80 Deferred
7.3CVSS 3.1 base score
0.35%EPSS exploitation probability, 30 days
NoNot in CISA KEV
0Affected product versions listed by NVD
2References
17 Jun 2026Last modified by NVD

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.

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N

References

LinkTags
https://github.com/YAFNET/YAFNET/security/advisories/GHSA-8rq5-wwpp-fmj2
https://github.com/YAFNET/YAFNET/security/advisories/GHSA-8rq5-wwpp-fmj2

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Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-43939), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.