CVE-2026-54118 in SQL Server
Summary
by MITRE • 07/14/2026
Deserialization of untrusted data in SQL Server allows an authorized attacker to execute code over a network.
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Analysis
by VulDB Data Team • 07/14/2026
This vulnerability represents a critical deserialization flaw that exploits the trust relationship between authenticated users and the sql server database engine. The weakness occurs when sql server processes untrusted data structures that are serialized using insecure deserialization techniques, allowing an authenticated attacker to manipulate serialized objects in ways that trigger remote code execution. This type of vulnerability falls under the common weakness enumeration category CWE-502 which specifically addresses deserialization of untrusted data. The attack vector typically involves an authenticated user who can submit maliciously crafted serialized data through database interfaces or network protocols that sql server uses for communication. When the system attempts to deserialize this manipulated data, it executes arbitrary code on the target system with the privileges of the sql server service account.
The operational impact of this vulnerability extends far beyond simple data manipulation as it provides attackers with persistent access to the underlying database infrastructure and potentially broader network resources. An attacker who successfully exploits this weakness can execute commands on the sql server host system, potentially escalating privileges to SYSTEM level access depending on how the sql server service is configured. The vulnerability enables lateral movement within the network as sql server often has access to sensitive data repositories and may communicate with other systems using established trust relationships. From an attack framework perspective, this vulnerability maps to multiple ATT&CK techniques including execution through command and scripting interpreter, privilege escalation through service modification, and persistence via scheduled tasks or registry modifications that could be established during the initial exploitation phase.
Mitigation strategies must address both the immediate deserialization security gaps and broader architectural concerns within sql server deployments. Organizations should implement strict input validation and sanitization for all data entering the sql server environment, particularly around serialized objects used in database communication protocols. The principle of least privilege should be enforced by ensuring sql server service accounts operate with minimal necessary permissions and that database connections are properly segmented from critical network resources. Regular security assessments should focus on identifying all potential serialization points within sql server configurations and application interfaces that might expose the system to similar attacks. Additionally, implementing proper monitoring and logging of deserialization activities can help detect anomalous behavior indicative of exploitation attempts, while network segmentation can limit the lateral movement capabilities of successful attackers who manage to exploit this vulnerability.