YetAnotherForum.NET Vulnerability Allows Arbitrary SQL Execution by Low-Privileged Users
The National Vulnerability Database has identified a critical SQL injection vulnerability in YetAnotherForum.NET (YAF.NET) versions prior to 4.0.5. This flaw, tracked as CVE-2026-43937, allows any authenticated low-privileged user to execute arbitrary SQL commands. The vulnerability lies in the /Admin/RunSql handler, which fails to properly validate input before passing it directly to the database access layer. This bypasses necessary authorization checks, effectively granting elevated privileges to unprivileged users.
With a CVSS score of 8.8, this vulnerability poses a significant risk. Attackers can leverage this to exfiltrate sensitive data, modify existing records, or even drop tables, leading to complete data compromise. Given that YAF.NET is an ASP.NET forum application, the potential impact spans across numerous websites and online communities relying on this software for user interaction. Defenders must prioritize patching this vulnerability immediately.
The fix is available in YAF.NET version 4.0.5. Organizations running affected versions should upgrade without delay. For those unable to patch immediately, restricting access to the /Admin endpoints and closely monitoring database logs for suspicious RunSql queries can serve as interim mitigation, though a patch is the definitive solution.
What This Means For You
- If your organization uses YetAnotherForum.NET, check your version immediately and patch to 4.0.5 or later. If patching isn't feasible today, audit your `/Admin/RunSql` access logs for any anomalous activity and consider strict IP whitelisting for the admin interface.
Related ATT&CK Techniques
🛡️ Detection Rules
3 rules · 6 SIEM formats3 detection rules auto-generated for this incident, mapped to MITRE ATT&CK. Sigma YAML is free — export to any SIEM format via the Intel Bot.
CVE-2026-43937 - YetAnotherForum.NET Arbitrary SQL Execution via /Admin/RunSql
title: CVE-2026-43937 - YetAnotherForum.NET Arbitrary SQL Execution via /Admin/RunSql
id: scw-2026-05-12-ai-1
status: experimental
level: critical
description: |
Detects the specific endpoint '/Admin/RunSql' being accessed via POST, which is the entry point for arbitrary SQL execution in YetAnotherForum.NET versions prior to 4.0.5. This rule targets the direct abuse of the vulnerability by low-privileged users.
author: SCW Feed Engine (AI-generated)
date: 2026-05-12
references:
- https://shimiscyberworld.com/posts/nvd-CVE-2026-43937/
tags:
- attack.initial_access
- attack.t1190
logsource:
category: webserver
detection:
selection:
cs-uri|contains:
- '/Admin/RunSql'
cs-method|exact:
- 'POST'
condition: selection
falsepositives:
- Legitimate administrative activity
Source: Shimi's Cyber World · License & reuse
Indicators of Compromise
| ID | Type | Indicator |
|---|---|---|
| CVE-2026-43937 | SQLi | YetAnotherForum.NET (YAF.NET) versions prior to 4.0.5 |
| CVE-2026-43937 | SQLi | Vulnerable endpoint: /Admin/RunSql |
| CVE-2026-43937 | SQLi | Vulnerable function: OnPostRunQuery binding 'Editor' from POST body to IDbAccess.RunSql |
Written by SCW Vulnerability Desk
Source & Attribution
| Source Platform | NVD |
| Channel | National Vulnerability Database |
| Published | May 12, 2026 at 18:16 UTC |
This content was AI-rewritten and enriched by Shimi's Cyber World based on the original source. All intellectual property rights remain with the original author.
Believe this infringes your rights? Submit a takedown request.
Related coverage
Ivanti Endpoint Manager RCE via SQL Injection (CVE-2026-8111)
CVE-2026-8111 — SQL injection in the web console of Ivanti Endpoint Manager before version 2024 SU6 allows a remote authenticated attacker to achieve remote code execution.
Ivanti Endpoint Manager Privilege Escalation (CVE-2026-8110)
CVE-2026-8110 — Incorrect permissions assignment in the agent of Ivanti Endpoint Manager before version 2024 SU6 allows a local authenticated attacker to escalate their privileges.
CVE-2026-8109 — An exposed dangerous method on the Core Server of Ivanti
CVE-2026-8109 — An exposed dangerous method on the Core Server of Ivanti Endpoint Manager before version 2024 SU6 allows a remote authenticated attacker to leak access credentials.