CVE•Published 2026-05-12•Modified 2026-05-13•0 articles on news•6 live references•NVD data

CVE-2026-43939

Vulnerability data via NVD (ingested)

CVSS v3.1

7.3

HIGH

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

EPSS percentile

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Weaknesses (CWE)

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')CWE-80Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)CWE-116Improper Encoding or Escaping of Output

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.

Timeline

Published 2026-05-12

Modified 2026-05-13

External references

NVD MITRE Exploit-DB GitHub PoC Sploitus VulnCheck

Search for exposed instances

Shodan + Censys queries derived from NVD's CPE data. The vuln tag catches assets Shodan has explicitly linked to this CVE; the product / banner fingerprints find exposed instances even when the vuln tag was never applied (which is common).

Shodan · vuln tag0 hosts

vuln:CVE-2026-43939

Hosts Shodan has explicitly fingerprinted as vulnerable.

More intel sources (5)

Shodan report

vuln:CVE-2026-43939

Country / ASN / product breakdown for the vuln query.

Censys

vulnerabilities.cve_id: CVE-2026-43939

Censys host search filtered to this CVE id.

grep.app

CVE-2026-43939