CVE-2026-55855: MariaDB Connector/Node.js: Possible SQL injection in Buffer parameter escaping under big5/gbk/sjis/cp932/gb18030 client charsets

Vulnerability summary

CVE-2026-55855 is a medium (CVSS 6.5) vulnerability in mariadb-corporation mariadb-connector-nodejs. EPSS estimates a 0.69% chance of exploitation in the next 30 days, higher than 52.9% of scored vulnerabilities.

Timeline

1. 28-08-2026
   PublishedVulnerability first disclosed.
2. 31-08-2026
   Last modifiedVulnerability information updated.

Description

MariaDB Connector/Node.js is used to connect applications developed on Node.js to MariaDB and MySQL databases. Prior to 3.2.4, 3.3.3, 3.4.6, and 3.5.3, MariaDB Connector/Node.js permits SQL injection when attacker-controlled Buffer parameters are escaped client-side under the big5, gbk, sjis, cp932, or gb18030 client character sets. PacketOutputStream.writeBufferEscape in lib/io/packet-output-stream.js escaped bytes without the charset-aware getMbRecognizer logic in lib/misc/charset-mb.js. The server SQL lexer runs my_ismbchar before escape processing, so an attacker-controlled lead byte can consume the inserted 0x5C backslash as a multibyte trail byte and leave the following 0x27 quote unescaped, terminating the string literal and allowing arbitrary SQL. The default utf8mb4 character set and parameters sent through the execute binary prepared-statement path are not affected. Successful exploitation can expose or modify data available to the database account. This issue is fixed in versions 3.2.4, 3.3.3, 3.4.6, and 3.5.3.

• CWE-89Improper Neutralization of Special Elements used in an SQL CommandThe product constructs all or part of an SQL command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended SQL command when it is sent to a downstream component. Without sufficient removal or quoting of SQL syntax in user-controllable inputs, the generated SQL query can cause those inputs to be interpreted as SQL instead of ordinary user data.
• CWE-116Improper Encoding or Escaping of OutputThe product prepares a structured message for communication with another component, but encoding or escaping of the data is either missing or done incorrectly. As a result, the intended structure of the message is not preserved.