CVE-2025-4207 in PostgreSQL
Summary
by MITRE • 05/08/2025
Buffer over-read in PostgreSQL GB18030 encoding validation allows a database input provider to achieve temporary denial of service on platforms where a 1-byte over-read can elicit process termination. This affects the database server and also libpq. Versions before PostgreSQL 17.5, 16.9, 15.13, 14.18, and 13.21 are affected.
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Analysis
by VulDB Data Team • 11/07/2025
The vulnerability described in CVE-2025-4207 represents a critical buffer over-read condition within PostgreSQL's GB18030 encoding validation mechanism that can be exploited to cause temporary denial of service. This issue specifically impacts the database server's ability to process input data encoded in the GB18030 character set, which is commonly used for Chinese text processing. The flaw manifests when the system encounters malformed or specially crafted GB18030 encoded data during input validation, leading to memory access violations that can terminate database processes. The vulnerability affects multiple PostgreSQL versions including 13 through 17, with specific patch versions outlined for each major release line. The root cause stems from improper bounds checking during the validation of multibyte character sequences, where the validation logic reads beyond the allocated buffer boundaries.
The technical implementation of this vulnerability leverages the GB18030 encoding's complex structure which supports both 1-byte and 4-byte character representations, creating potential for over-read conditions when processing sequences that fall outside normal validation parameters. When a database input provider submits maliciously crafted GB18030 encoded data, the validation routine attempts to access memory locations beyond the intended buffer, potentially causing segmentation faults or process termination depending on the target platform's memory management characteristics. This over-read condition specifically impacts platforms where 1-byte over-reads can trigger immediate process termination rather than graceful error handling. The vulnerability affects both the server-side processing and the client-side libpq library, indicating a systemic issue within the encoding validation framework that extends beyond the core database engine.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise database availability and integrity within affected systems. Attackers who can influence database input through injection vectors or data manipulation capabilities can exploit this weakness to cause temporary database outages, leading to service degradation or complete unavailability of database services. The vulnerability's scope across multiple PostgreSQL versions means that organizations running any of the affected releases face potential exposure, with the risk of denial of service attacks being particularly concerning in production environments where database availability is critical. The impact is amplified by the fact that GB18030 encoding is widely used in Asian language applications, making this vulnerability relevant to organizations with internationalized database deployments.
Mitigation strategies for CVE-2025-4207 primarily focus on immediate patching of affected PostgreSQL installations to the recommended versions that contain the necessary fixes for the buffer over-read condition. Organizations should prioritize updating their database servers and any applications using libpq to ensure complete protection against this vulnerability. Additional defensive measures include implementing input validation at application layers to filter potentially malicious GB18030 encoded data before it reaches the database engine, although this approach provides only partial protection as the vulnerability exists within the core validation logic. Security monitoring should be enhanced to detect unusual patterns of database process termination or memory access violations that might indicate exploitation attempts. The vulnerability aligns with CWE-125 buffer over-read and CWE-248 unspecified vulnerability categories, while its exploitation patterns correspond to attack techniques in the ATT&CK framework related to service disruption and resource exhaustion. Organizations should also consider implementing network segmentation and access controls to limit exposure of database systems to potential attack vectors that could leverage this vulnerability for unauthorized access or service disruption.