SQL Server Elevation of Privilege VulnerabilityVendor advisorypatch
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21262 CVE-2026-21262
HIGH
SQL Server Elevation of Privilege Vulnerability
Record summary
CVE-2026-21262 has a selected CVSS score of 8.8 (high); EIP currently links 1 curated repository PoC.
Description
Improper access control in SQL Server allows an authorized attacker to elevate privileges over a network.
Description source: GitHub Advisory
Exploitation context
Known exploitation
- VulnCheck KEV
- Listed · Apr 13, 2026 · VulnCheck
- Reported exploitation
- Observed · VulnCheck
Available material
- Curated repository PoCs
- 1
CISA SSVC decision
ExploitationNone
AutomatableNo
Technical impactTotal
CISA Coordinator · SSVC 2.0.3 · Evaluated Mar 5, 2026 · Source: CVE List
Affected products and versions
11| Product | Source | Version range | Status |
|---|---|---|---|
Microsoft SQL Server 2016 Service Pack 3 (GDR)Browse Microsoft / Microsoft SQL Server 2016 Service Pack 3 (GDR) | CVE List | 13.0.0 to < 13.0.6480.4 | affected |
Microsoft SQL Server 2016 Service Pack 3 Azure Connect Feature PackBrowse Microsoft / Microsoft SQL Server 2016 Service Pack 3 Azure Connect Feature Pack | CVE List | 13.0.0 to < 13.0.7075.5 | affected |
Microsoft SQL Server 2017 (CU 31)Browse Microsoft / Microsoft SQL Server 2017 (CU 31) | CVE List | 14.0.0 to < 14.0.3520.4 | affected |
Microsoft SQL Server 2017 (GDR)Browse Microsoft / Microsoft SQL Server 2017 (GDR) | CVE List | 14.0.0 to < 14.0.2100.4 | affected |
Microsoft SQL Server 2019 (CU 32)Browse Microsoft / Microsoft SQL Server 2019 (CU 32) | CVE List | 15.0.0.0 to < 15.0.4460.4 | affected |
Microsoft SQL Server 2019 (GDR)Browse Microsoft / Microsoft SQL Server 2019 (GDR) | CVE List | 15.0.0 to < 15.0.2160.4 | affected |
Microsoft SQL Server 2022 (GDR)Browse Microsoft / Microsoft SQL Server 2022 (GDR) | CVE List | 16.0.0 to < 16.0.1170.5 | affected |
Microsoft SQL Server 2022 for x64-based Systems (CU 23)Browse Microsoft / Microsoft SQL Server 2022 for x64-based Systems (CU 23) | CVE List | 16.0.0.0 to < 16.0.4240.4 | affected |
Microsoft SQL Server 2025 (CU 2)Browse Microsoft / Microsoft SQL Server 2025 (CU 2) | CVE List | 17.0.0.0 to < 17.0.4020.2 | affected |
Microsoft SQL Server 2025 for x64-based Systems (GDR)Browse Microsoft / Microsoft SQL Server 2025 for x64-based Systems (GDR) | CVE List | 17.0.1050.2 to < 17.0.1105.2 | affected |
sql_server_2016Browse Microsoft / sql_server_2016 | VulnCheck | Version data not supplied | |
Proofs of concept
1Curated repository PoCs
GitHubCVE-2026-26118Curated repository PoCby SecureWithUmerStars: 34Scanner19 files
Analysis
Technical assessment
A Microsoft Sentinel analytics rule (KQL query) designed to detect a multi-stage attack chain involving Azure MCP Server managed identity abuse. It correlates MCP-related service principal sign-ins with subsequent privileged Azure operations (e.g., Key Vault access, role assignment modification) within a 30-minute window.
Backdoor review
No backdoor observed in reviewed code
The supplied evidence is a single JSON file defining a Microsoft Sentinel analytics rule for detecting post-exploitation activity related to CVE-2026-26118. The file contains only declarative KQL query logic and rule configuration; no executable code, obfuscation, or deceptive behavior is present.
ClassificationScanner
Model confidence95%
AuthenticationUnknown
Languages
Target software
Attack types
Evidence & reasoningClassification basis · observed behavior · safety review
Classification basis and observed behavior
Classification basis
The artifact is a Microsoft Sentinel scheduled analytics rule (JSON definition with an embedded KQL query) that detects post-exploitation activity. It does not contain any code to exploit a vulnerability; it only checks for indicators of compromise in log data.
j-dahl7-mcp-attack-detection-sentinel-a074553/analytics-rules/mcp-identity-post-exploitation.json:2-8Requirements
- Requires Microsoft Sentinel workspace with AADServicePrincipalSignInLogs and AzureActivity log data ingestion enabled.
j-dahl7-mcp-attack-detection-sentinel-a074553/analytics-rules/mcp-identity-post-exploitation.json:8
Observed behavior
- Defines a KQL query that joins AADServicePrincipalSignInLogs with AzureActivity logs to find successful privileged operations performed by an MCP-related service principal within 30 minutes of its sign-in.
j-dahl7-mcp-attack-detection-sentinel-a074553/analytics-rules/mcp-identity-post-exploitation.json:8 - The rule is configured to run every hour, look back over 1 day, and create an incident when any matching event is found.
j-dahl7-mcp-attack-detection-sentinel-a074553/analytics-rules/mcp-identity-post-exploitation.json:9-12
Behaviors behind the backdoor verdict
Observables
- Analytics Rule
- Payload withheldThe file is a Microsoft Sentinel scheduled analytics rule that correlates Azure MCP service principal sign-ins with subsequent privileged operations to detect potential abuse of managed identity tokens.
j-dahl7-mcp-attack-detection-sentinel-a074553/analytics-rules/mcp-identity-post-exploitation.json:1-58
What the analysis did not establish
- Only one text file (the analytics rule definition) was provided; the repository unit contains 18 other files (including 2 non-text media files) that were not included in the evidence packet.
- The evidence does not include any exploit code, proof-of-concept scripts, or technical writeups describing how to trigger the associated CVEs.
- Only one text file was provided; 2 non-text media files and 16 unclassified files were present in the artifact but not analyzed. Their content is unknown.
Model interpretation
This review is limited to the supplied PoC code and context. It does not assert that the code works or is safe to execute.
References
2nvd.nist.gov
https://nvd.nist.gov/vuln/detail/CVE-2026-21262