CVE-2026-7771
Summary
by MITRE • 07/17/2026
IBM Db2 11.5.0 through 11.5.9, and 12.1.0 through 12.1.4 is vulnerable to a trap when compiling a specially crafted statements containing subqueries could lead to a denial of service.
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Analysis
by VulDB Data Team • 07/17/2026
This vulnerability affects IBM Db2 database systems across multiple versions including 11.5.0 through 11.5.9 and 12.1.0 through 12.1.4, representing a critical security flaw that manifests during query compilation processes. The issue stems from improper handling of specially crafted SQL statements containing subqueries which can trigger unexpected system behavior leading to service disruption. When the database engine encounters these malformed statements during compilation, it enters an unstable state that results in denial of service conditions affecting database availability and accessibility for legitimate users.
The technical nature of this vulnerability aligns with CWE-129, which addresses improper handling of potentially malicious input data during processing operations. The flaw specifically occurs within the query compilation phase where the system fails to properly validate or sanitize subquery structures before attempting execution. This represents a classic buffer over-read or trap condition that can be exploited by attackers who craft malicious SQL statements designed to trigger the vulnerable code path. The vulnerability operates at the database engine level rather than at network protocols, making it particularly insidious as it can be triggered through legitimate database connections.
The operational impact of this vulnerability extends beyond simple service interruption to potentially compromise database integrity and availability for critical business operations. Organizations relying on these Db2 versions may experience extended downtime during attack scenarios, with potential cascading effects on applications dependent on database connectivity. The vulnerability particularly affects systems where complex queries involving subqueries are common, which is typical in enterprise environments with sophisticated data analysis requirements. Attackers could exploit this weakness to systematically disrupt database services, potentially causing financial losses and operational disruptions.
Mitigation strategies should prioritize immediate patching of affected versions to address the root cause through official IBM security updates. Organizations should implement input validation measures at application level to filter out suspicious query patterns before they reach the database engine. Network segmentation and access controls can help limit exposure by restricting direct database connections from untrusted sources. Additionally, monitoring systems should be configured to detect unusual query patterns or repeated compilation failures that may indicate exploitation attempts. The vulnerability demonstrates the importance of comprehensive testing for edge cases in database query processing and highlights the need for robust error handling mechanisms in enterprise database systems. Organizations should also consider implementing database activity monitoring solutions that can detect and alert on anomalous query behavior indicative of potential exploitation attempts.
This vulnerability type falls under ATT&CK technique T1499 which covers network denial of service attacks, specifically targeting database availability through exploitation of software weaknesses. The attack vector represents a significant threat to database-centric applications and requires coordinated response efforts involving both application security teams and database administrators. Regular security assessments should include testing for similar edge case vulnerabilities in database systems, particularly focusing on query compilation and execution phases where malformed input can cause system instability.