CVE-2026-14664 in PostgreSQL
Summary
by MITRE • 08/13/2026
Heap buffer overflow in PostgreSQL regexp allows the query author to execute arbitrary code as the operating system user running the database, via text that would not pass encoding validation. This shares heritage with CVE-2026-2006, but this case involved unanticipated data growth when round-tripped through pg_wchar. 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 heap buffer overflow vulnerability in PostgreSQL represents a critical security flaw that enables remote code execution through crafted regular expression patterns. The vulnerability arises from improper handling of text encoding validation during regex operations, specifically when processing data that undergoes round-trip conversion through the pg_wchar encoding system. Attackers can exploit this by crafting malicious text input that appears valid but triggers unexpected memory allocation behavior when processed through PostgreSQL's regular expression engine. The flaw operates at the intersection of buffer management and character encoding validation, creating a pathway for arbitrary code execution with the privileges of the database service account.
The technical implementation of this vulnerability stems from how PostgreSQL handles multibyte character sequences during regex processing. When text data containing certain byte patterns is processed through the pg_wchar conversion functions, the system allocates insufficient heap memory to accommodate the expanded representation during the encoding validation phase. This memory miscalculation creates a condition where subsequent operations can overwrite adjacent memory regions, potentially allowing attackers to inject and execute malicious code within the database process context. The vulnerability specifically manifests when text undergoes transformation through pg_wchar encoding functions, which is a standard part of PostgreSQL's internationalization support.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass complete system compromise when the database service runs with elevated privileges. Since the execution occurs within the database process environment, attackers can leverage this to access sensitive data, modify database contents, or potentially pivot to other systems if the database server has network access to additional resources. The severity is amplified by the fact that this vulnerability affects multiple major PostgreSQL versions, creating widespread exposure across different deployment scenarios and organizational environments.
Mitigation strategies should focus on immediate patching of affected PostgreSQL versions to the latest releases containing the fix. Organizations should also implement strict input validation procedures for all regex operations and consider disabling unnecessary regular expression functionality where possible. Network segmentation can help limit potential exploitation by restricting direct database access, while monitoring systems should be deployed to detect unusual patterns in database query execution that might indicate exploitation attempts. The vulnerability aligns with CWE-121 Heap-based Buffer Overflow and maps to ATT&CK technique T1059 Command and Scripting Interpreter, specifically targeting the database service environment for privilege escalation and code execution.
This vulnerability demonstrates the complexity of modern database security where encoding validation issues can create unexpected attack surfaces. The connection to CVE-2026-2006 indicates a pattern of similar encoding-related flaws in PostgreSQL's internationalization handling, emphasizing the need for comprehensive testing of character encoding pathways in database systems. Organizations should conduct thorough vulnerability assessments focusing on text processing functions and ensure that all database components undergo regular security reviews to identify potential memory corruption issues in encoding and decoding operations.