Vulnerability · Published May 12, 2026 · Assigned by GitHub_M

CVE-2026-43937YAF.NET: Pre-Handler Authorization Bypass on Admin Pages Enabling Blind SQL Execution via `/Admin/RunSql`

High 8.8

In plain English

A high-severity SQL injection in YAFNET from YAFNET. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 42% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.8High

Exploit odds (30 days)0.5%top 57.7% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

YetAnotherForum.NET (YAF.NET) is a C# ASP.NET forum. Prior to 4.0.5, Any admin OnPost… handler executes its side effects before the ResultFilterAttribute rewrites the response to a 302 to /Info/4. The most impactful abuse is /Admin/RunSql, whose OnPostRunQuery binds Editor from the POST body and passes it straight to IDbAccess.RunSql with no caller check, yielding arbitrary SQL execution for any low-privileged user. This vulnerability is fixed in 4.0.5.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
NuGet	yafnet.core	4.0.5	GHSA-xhw7-j96h-c3g5

Affected products (as reported)

Vendor	Product	Versions
YAFNET	YAFNET	< 4.0.5

Weakness: CWE-89, CWE-841 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References

https://github.com/YAFNET/YAFNET/security/advisories/GHSA-xhw7-j96h-c3g5 x_refsource_CONFIRM