CVE-2026-111439 in openGauss-server
Summary
by MITRE • 10/19/2026
在 openGauss-server的 src/common/backend/utils/adt/genfile.cpp 模块中，内置函数 pg_read_binary_file_blocks() 存在权限校验逻辑缺陷。该函数在入口处仅校验了起始块号（startBlockNum）和块数量（blockCount）的范围，随后直接调用底层文件读取例程 ReadBinaryFileBlocksFirstCall()。该底层例程仅执行了路径规范化检查以及针对 .. 路径遍历和数据目录边界的基本检查，缺失了对调用者数据库权限（如 SELECT 权限）的校验。此外，辅助函数 is_row_data_file() 也仅用于识别文件形态，未包含权限检查。因此，任何拥有普通数据库连接权限的用户，只要能够通过 pg_relation_filepath() 等函数获取到目标表的底层关系文件路径（例如压缩数据的 _compress 文件路径），即可无需具备该表的 SELECT 权限，直接读取表数据的二进制块。 此漏洞影响此前3.0.0到6.0.0间的所有版本及补丁版，并在7.0.0-LTS版本修复。修复patch详见：https://gitcode.com/opengauss/openGauss-server/pull/9374。
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Analysis
by VulDB Data Team • 10/19/2026
The vulnerability identified in openGauss-server versions ranging from 3.0.0 to 6.0.0, including all patch releases within this range but resolved in version 7.0.0-LTS, centers on a critical authorization bypass flaw within the internal function pg_read_binary_file_blocks(). Located in the src/common/backend/utils/adt/genfile.cpp module, this built-in utility is designed to read binary blocks from database files directly at the storage level. The core technical deficiency lies in the insufficient access control logic implemented during the entry point of this function. Specifically, while the code performs basic validation checks on input parameters such as startBlockNum and blockCount to ensure they fall within acceptable numerical ranges, it completely omits any verification of the calling user's database privileges relative to the target file or relation. This oversight allows the execution flow to proceed directly to the underlying ReadBinaryFileBlocksFirstCall() routine without confirming whether the authenticated session possesses the necessary SELECT permissions on the specific table associated with the requested data blocks.
The subsequent layer of protection, handled by the internal helper function is_row_data_file(), serves primarily to identify file types and perform rudimentary path normalization checks along with basic safeguards against directory traversal attacks involving double-dot sequences or boundary violations relative to the data directory root. However, this mechanism does not extend to checking object-level permissions on database tables. Consequently, an attacker who has established a standard connection to the openGauss instance can exploit this gap by leveraging other available functions such as pg_relation_filepath() to discover the physical file paths of target relations. By obtaining these internal storage paths, particularly for compressed data files identified with extensions like _compress, the attacker can invoke pg_read_binary_file_blocks() to read raw binary blocks containing sensitive table data without ever having been granted explicit SELECT privileges on that specific relation. This represents a classic case where low-level file system access is decoupled from high-level database object security policies.
From an industry standard perspective, this vulnerability aligns with CWE-269, which describes Improper Privilege Management, specifically highlighting the failure to enforce proper authorization checks before performing sensitive operations. Furthermore, it maps closely to MITRE ATT&CK technique T1005, Data from Local System, as well as sub-techniques related to file and directory discovery such as T1083. The exploitation of this flaw allows for unauthorized data exfiltration at the storage layer, bypassing standard SQL-level access controls that are typically enforced by the query planner and executor components of the database engine. This architectural disconnect between physical file I/O operations and logical table permissions creates a significant security gap where internal administrative or diagnostic functions can be misused to circumvent intended data isolation boundaries.
The operational impact of this vulnerability is severe, as it enables any authenticated user with basic connectivity rights to read arbitrary binary blocks from database files belonging to other users or protected tables. This capability effectively nullifies the confidentiality guarantees provided by row-level security and standard permission models within openGauss. Attackers can extract sensitive information such as personally identifiable data, financial records, or proprietary business logic stored in compressed formats without triggering typical audit alerts associated with unauthorized SELECT statements. The ability to read raw binary blocks also opens avenues for further exploitation, including potential buffer overflow scenarios if the block size parameters are manipulated maliciously alongside this privilege bypass, although the primary risk remains direct data leakage.
To mitigate this vulnerability, organizations running affected versions of openGauss must apply the specific patch referenced in pull request 9374 on GitCode, which addresses these issues in version 7.0.0-LTS and later releases. The fix involves integrating proper privilege checks into the pg_read_binary_file_blocks() function to verify that the calling user holds appropriate SELECT permissions for the target relation before allowing access to its underlying storage files. Until an upgrade is feasible, database administrators should restrict direct execution of this internal function by revoking execute privileges from public or untrusted roles if possible. Additionally, implementing strict network segmentation and monitoring for unusual patterns in file I/O operations can help detect potential exploitation attempts. Regular audits of user permissions and minimizing the exposure of diagnostic functions to non-administrative users are essential defensive measures to reduce the attack surface associated with low-level database utilities.