Microsoft Patches Critical SQL Server Privilege Escalation Flaw (CVE-2026-20803)
On January 13, 2026, Microsoft released security updates to address a critical elevation of privilege vulnerability in SQL Server, tracked as CVE-2026-20803. The flaw allows authenticated attackers to bypass authentication controls and gain elevated system privileges remotely, posing a significant risk to affected systems.
The vulnerability stems from missing authentication mechanisms in the database engine and impacts multiple SQL Server versions, including SQL Server 2022 and 2025. With a CVSS score of 7.2, Microsoft rated the issue as "Important" severity. End-of-life SQL Server instances, which no longer receive security updates, are particularly vulnerable, as attackers actively target known weaknesses in unpatched systems.
Organizations running affected versions are advised to apply the latest patches promptly. For systems that cannot be upgraded, mitigation measures such as isolation, restricted access, and heightened monitoring are recommended to reduce exposure. The flaw also introduces risks related to memory dumping in SQL Server 2022 and 2025, further emphasizing the need for immediate action.
Source: https://www.linkedin.com/feed/update/urn:li:activity:7417759373843763201
Microsoft Security cybersecurity rating report: https://www.rankiteo.com/company/microsoft-security
"id": "MIC1768537039",
"linkid": "microsoft-security",
"type": "Vulnerability",
"date": "1/2026",
"severity": "25",
"impact": "1",
"explanation": "Attack without any consequences"{'affected_entities': [{'industry': 'Software',
'name': 'Microsoft',
'type': 'Technology Company'}],
'attack_vector': 'Network',
'date_publicly_disclosed': '2026-01-13',
'description': 'Microsoft released security updates addressing a critical '
'elevation of privilege vulnerability in SQL Server that '
'enables authorized attackers to bypass authentication '
'controls and gain elevated system privileges remotely. The '
'flaw stems from missing authentication mechanisms for '
'critical functions within the database engine.',
'impact': {'systems_affected': 'SQL Server 2022, SQL Server 2025, and '
'end-of-life SQL Server versions'},
'lessons_learned': 'End-of-life SQL servers increase risk due to lack of '
'security updates. Attackers actively target these '
'systems. Patch management and system isolation are '
'critical.',
'post_incident_analysis': {'corrective_actions': 'Security updates released '
'to address the '
'vulnerability',
'root_causes': 'Missing authentication mechanisms '
'for critical functions within the '
'SQL Server database engine'},
'recommendations': ['Apply security updates immediately for SQL Server 2022 '
'and 2025',
'Isolate end-of-life SQL servers if they cannot be '
'upgraded',
'Limit access to vulnerable systems',
'Enhance monitoring for suspicious activity',
'Prioritize patching for vulnerabilities with high CVSS '
'scores'],
'references': [{'source': 'AI-Powered Free Security-Audit Checklist for 2026 '
'– ISO 27001, SOC 2, NIST, NIS 2 and GDPR '
'Compliance'}],
'response': {'containment_measures': 'Isolate end-of-life SQL servers, limit '
'access, and monitor activity closely',
'enhanced_monitoring': 'Recommended for end-of-life SQL servers',
'remediation_measures': 'Apply security updates released on '
'January 13, 2026'},
'title': 'Microsoft SQL Server Elevation of Privilege Vulnerability '
'(CVE-2026-20803)',
'type': 'Elevation of Privilege',
'vulnerability_exploited': 'CVE-2026-20803'}