Sysown ProxySQL up to 3.0.9/3.1.9/4.0.9 MySQL Data Stream mysql_data_stream.cpp decompress_mysql_payload code injection

Summaryinfo

A vulnerability, which was classified as critical, was found in Sysown ProxySQL up to 3.0.9/3.1.9/4.0.9. Affected is the function decompress_mysql_payload of the file lib/mysql_data_stream.cpp of the component MySQL Data Stream. Executing a manipulation can lead to code injection. This vulnerability appears as CVE-2026-102664. The attack may be performed from remote. There is no available exploit. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in Sysown ProxySQL up to 3.0.9/3.1.9/4.0.9. It has been declared as critical. This vulnerability affects the function decompress_mysql_payload of the file lib/mysql_data_stream.cpp of the component MySQL Data Stream. The manipulation with an unknown input leads to a code injection vulnerability. The CWE definition for the vulnerability is CWE-94. The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

ProxySQL is a proxy for MySQL and its forks, as well as PostgreSQL. Prior to 3.0.10, 3.1.10, and 4.0.10, decompress_mysql_payload() in lib/mysql_data_stream.cpp accepts a zlib stream when uncompress() returns Z_OK without checking that the actual output length equals the attacker-controlled payload_length. An authenticated MySQL client that negotiates compression can overstate payload_length, causing buffer2array() to parse the uninitialized tail of a heap buffer as MySQL packet headers and forward stale data to the backend. Backend error responses can disclose prior SQL queries, result data, credentials, or session state, and malformed lengths can also cause excessive allocations. This issue is fixed in versions 3.0.10, 3.1.10, and 4.0.10.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-102664 since 09/29/2026. The exploitation appears to be easy. The attack can be initiated remotely. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1059.

Upgrading to version 3.0.10, 3.1.10 or 4.0.10 eliminates this vulnerability.

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Productinfo

Type

• Firewall Software

Vendor

• Sysown

Name

• ProxySQL

Version

• 3.0.0
• 3.0.1
• 3.0.2
• 3.0.3
• 3.0.4
• 3.0.5
• 3.0.6
• 3.0.7
• 3.0.8
• 3.0.9
• 3.1.0
• 3.1.1
• 3.1.2
• 3.1.3
• 3.1.4
• 3.1.5
• 3.1.6
• 3.1.7
• 3.1.8
• 3.1.9
• 4.0.0
• 4.0.1
• 4.0.2
• 4.0.3
• 4.0.4
• 4.0.5
• 4.0.6
• 4.0.7
• 4.0.8
• 4.0.9

Website

• Product: https://github.com/sysown/proxysql/

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