CVE-2026-14678 in PostgreSQL
Summary
by MITRE • 08/13/2026
Buffer over-read in PostgreSQL pg_trgm index picksplit function reads past end of a heap buffer. This might allow a table maintainer to infer limited memory values, via the lossy signal of index split choices. Versions before PostgreSQL 18.5, 17.11, 16.15, 15.19, and 14.24 are affected.
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Analysis
by VulDB Data Team • 08/13/2026
This vulnerability represents a critical buffer over-read condition within the postgresql pg_trgm extension's index picksplit function implementation. The flaw occurs when processing heap buffers during index maintenance operations, specifically when the system attempts to split index entries. The technical implementation fails to properly validate buffer boundaries, allowing memory access beyond allocated heap buffer limits. This issue manifests in the trigram index functionality that is commonly used for text pattern matching and similarity searches across large datasets.
The operational impact of this vulnerability extends beyond simple memory corruption as it creates a potential information disclosure channel through what is known as a lossy signal attack vector. An attacker with table maintenance privileges can potentially infer limited memory values by observing the patterns in index split choices that occur during normal database operations. This type of information leakage, while not providing direct access to arbitrary memory contents, could reveal sensitive data patterns that aid in further exploitation attempts or provide insights into system internals.
The vulnerability affects multiple PostgreSQL release branches including versions before 18.5, 17.11, 16.15, 15.19, and 14.24, indicating this is a long-standing issue that has persisted across major release lines. This widespread impact suggests the flaw exists in core index maintenance logic rather than being isolated to specific functionality. The vulnerability aligns with CWE-125 Uninitialized Read and may also relate to CWE-787 Out-of-bounds Write patterns when considering the broader context of buffer management issues.
From a threat modeling perspective, this vulnerability operates under the ATT&CK framework's technique T1068 Exploitation for Privilege Escalation and T1552 Credential Access. While it does not directly provide privilege escalation capabilities, the ability to infer memory values through index operations represents a form of information gathering that could be leveraged in combination with other attacks. The attack vector requires table maintenance privileges, which typically includes roles with ALTER or INSERT permissions on affected tables.
Database administrators should prioritize patching affected systems to address this vulnerability, particularly in environments where multiple users have table maintenance capabilities. The recommended mitigation strategy involves upgrading to the patched versions while maintaining proper access controls and monitoring for unusual index maintenance patterns that might indicate exploitation attempts. Additionally, implementing network segmentation and limiting table maintenance privileges can provide defense-in-depth measures against potential abuse of this vulnerability.
The root cause analysis reveals a fundamental flaw in buffer boundary checking within the index split logic, suggesting that similar issues may exist in other parts of the postgresql codebase where heap buffer operations occur. This highlights the importance of comprehensive code review processes specifically focused on memory safety and buffer management in database systems. The vulnerability demonstrates how seemingly benign index maintenance operations can expose security weaknesses when proper bounds checking is not implemented throughout all code paths. Organizations should conduct thorough security assessments of their database environments to identify and remediate similar buffer-related vulnerabilities that might exist in other extensions or core functionality.
This particular vulnerability serves as an example of how database security requires attention to both traditional attack surfaces and less obvious areas such as index maintenance operations. The complexity of modern database systems means that even specialized functions like trigram indexing can contain security flaws that impact overall system integrity. Proper testing methodologies including fuzzing and boundary condition analysis should be employed when developing database extensions to prevent similar issues from occurring in the future.