dbcve.org
SQL InjectionWeakness · CWE-89

CVE-2026-43937

HIGH · 8.8 CVSS v3.1 Published 2026-05-12
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
94/100
Remediation priority · Urgent
Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

YAF.NET versions prior to 4.0.5 have a missing function-level access control vulnerability in the /Admin/RunSql endpoint. The OnPostRunQuery handler binds the Editor parameter directly from POST data and passes it to IDbAccess.RunSql without any authorization check, allowing any authenticated user (including low-privileged users) to execute arbitrary SQL commands. The vulnerability is compounded by a race condition where admin handlers execute before the ResultFilterAttribute can redirect unauthorized access.

MitigationUpgrade to YAF.NET version 4.0.5 or later. Until then, disable or restrict access to the RunSql functionality at the web server or application level.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify YAF.NET version
    Locate the YAF.NET assembly files (typically in the /bin directory) or check version information in web.config/appSettings. Compare the installed version number against the affected range (versions prior to 4.0.5).
    Affected if The installed version is lower than 4.0.5.
  2. Verify /Admin/RunSql endpoint exists
    Check if the RunSql handler file exists in the application's admin directory or attempt a HEAD request to /Admin/RunSql to confirm the endpoint is registered.
    Affected if The endpoint is present and accessible.
  3. Check for low-privileged authenticated users
    Review the user database or user configuration to determine if non-admin users exist in the system who could potentially access the vulnerable endpoint.
    Affected if Low-privileged or standard users exist in the system.
  4. Confirm authorization bypass condition
    Verify that the ResultFilterAttribute or any authorization filter is applied to admin handlers. Check the order of filter execution in the request pipeline to confirm the race condition exists.
    Affected if Authorization filters execute after the admin handler logic or are not applied to the RunSql endpoint.

You are affected if YAF.NET version is below 4.0.5 AND the /Admin/RunSql endpoint exists AND low-privileged users can authenticate to the application.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade to YAF.NET version 4.0.5 or later. Until then, disable or restrict access to the RunSql functionality at the web server or application level.

Recommended fix High confidence

4.0.5

  1. Backup your existing database and application files before proceeding
  2. Identify your current YAF.NET version by checking the assemblies or admin panel
  3. Download YAF.NET version 4.0.5 from the official GitHub releases page (github.com/YAFNET/YAFNET)
  4. Deploy the new version files to your web server, replacing the existing files
  5. Verify the application runs correctly and test the /Admin/RunSql functionality to confirm the vulnerability is patched
  6. Ensure your database is intact and all forum functionality works as expected

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-43937 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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