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.

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Vendors Products
Advisories
Source ID Title
Github GHSA Github GHSA GHSA-8rq5-wwpp-fmj2 YAFNET has Stored XSS in Forum Thread Posts/Replies that Allows Arbitrary JavaScript Execution for All Thread Viewers
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Wed, 13 May 2026 15:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Wed, 13 May 2026 11:00:00 +0000

Type Values Removed Values Added
First Time appeared Yafnet
Yafnet yafnet
Vendors & Products Yafnet
Yafnet yafnet

Tue, 12 May 2026 15:00:00 +0000

Type Values Removed Values Added
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.
Title YAF.NET: Stored XSS in Forum Thread Posts/Replies Allowing Arbitrary JavaScript Execution for All Thread Viewers
Weaknesses CWE-116
CWE-79
CWE-80
References
Metrics cvssV3_1

{'score': 7.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-05-13T14:38:25.692Z

Reserved: 2026-05-04T16:59:09.089Z

Link: CVE-2026-43939

cve-icon Vulnrichment

Updated: 2026-05-13T14:33:10.309Z

cve-icon NVD

Status : Deferred

Published: 2026-05-12T15:16:15.647

Modified: 2026-05-13T18:24:58.737

Link: CVE-2026-43939

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-13T10:38:52Z

Weaknesses