Vulnerability in Sysown Proxysql
CVE-2026-102664
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.
Published .
CVSS v3 metric
CVSS v3 base score 7.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:L.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
- Sysown Proxysql — versions < 3.0.10, >= 3.1.0, < 3.1.10, >= 4.0.0, < 4.0.10
Weakness classification (CWE)
References
- https://github.com/sysown/proxysql/commit/396c742f7d50b1f479e1157e296ee9d0aff1b724
- https://github.com/sysown/proxysql/commit/a8c1cef4d44c4beea7f6aa21b8a09a7cb8c75520
- https://github.com/sysown/proxysql/releases/tag/v3.0.10
- https://github.com/sysown/proxysql/releases/tag/v3.1.10
- https://github.com/sysown/proxysql/releases/tag/v4.0.10
- https://github.com/sysown/proxysql/security/advisories/GHSA-fvch-fpgq-pwfx
Frequently asked questions
- What is CVE-2026-102664?
- CVE-2026-102664 is a high-severity vulnerability in Sysown Proxysql, classified under Use of Uninitialized Resource. CVSS score: 7.1/10. Published 2026-11-04.
- How severe is CVE-2026-102664?
- High severity. CVSS v3 base score is 7.1 out of 10.