CVE-2026-55002 in SQL Server
Summary
by MITRE • 07/14/2026
External control of file name or path in SQL Server allows an authorized attacker to elevate privileges locally.
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Analysis
by VulDB Data Team • 07/14/2026
This vulnerability represents a critical privilege escalation flaw within Microsoft SQL Server that enables authenticated attackers to manipulate file paths and potentially execute arbitrary code with elevated permissions. The issue stems from insufficient input validation in SQL Server's handling of external file name and path parameters, allowing malicious actors who already possess legitimate authentication credentials to exploit this weakness for unauthorized system access. When SQL Server processes external file references through its database engine, it fails to adequately sanitize or validate the provided paths, creating an attack surface where crafted inputs can bypass normal security boundaries.
The technical exploitation occurs when an attacker with valid database credentials submits malicious file path parameters that traverse directory structures or manipulate file handling operations within the SQL Server environment. This vulnerability falls under the CWE-73 category of "External Control of File Name or Path" and aligns with ATT&CK technique T1059.008 for Command and Scripting Interpreter. The flaw specifically manifests in SQL Server's implementation of external data processing functions that allow file system interactions, where the server accepts user-supplied paths without proper validation mechanisms. Attackers can leverage this weakness to access files outside of intended directories, potentially reading sensitive configuration files, accessing system binaries, or manipulating database backup operations.
The operational impact of this vulnerability extends beyond simple privilege escalation as it provides attackers with opportunities to establish persistent access, extract confidential data, or disrupt database services entirely. An attacker who successfully exploits this flaw can potentially read system registry keys, access encrypted database backups, or manipulate SQL Server's configuration files to maintain long-term access. The vulnerability is particularly dangerous because it requires only authentication credentials, meaning that any user with legitimate database access can attempt exploitation without needing additional privileged accounts.
Mitigation strategies should focus on implementing comprehensive input validation at multiple layers of the SQL Server architecture including database engine level restrictions, application-level parameter sanitization, and strict file system permission controls. Organizations should enforce principle of least privilege for all SQL Server accounts, implement proper network segmentation, and utilize SQL Server's built-in security features such as contained databases and restricted file access policies. Additionally, regular security assessments should validate that external file operations are properly constrained and that no unnecessary file system access permissions exist for database service accounts. The implementation of database auditing and monitoring solutions can help detect anomalous file access patterns that may indicate exploitation attempts, while adherence to security frameworks such as the Center for Internet Security (CIS) benchmarks provides recommended configurations to reduce attack surface.