This client-side error occurs when calling deprecated or insecure MySQL C API functions. The error warns developers to replace unsafe functions with their modern, secure alternatives.
The CR_INSECURE_API_ERR (error code 2062) is a client-side error introduced in MySQL 5.7.6 that prevents the use of deprecated or insecure API functions in the MySQL C API. When your application calls an unsafe function, MySQL returns this error along with a message suggesting which function to use instead. This error is a protective mechanism designed to prevent security vulnerabilities and compatibility issues. The most common trigger is using `mysql_real_escape_string()` when the server has the NO_BACKSLASH_ESCAPES SQL mode enabled, as this function cannot properly escape strings in that context. The error message typically follows the format: "Insecure API function call: 'function_name' Use instead: 'alternative_function'". This makes it clear which deprecated function was called and what the recommended replacement is.
Check the full error message to see which function is flagged as insecure. The error will specify both the problematic function and its recommended replacement.
Common examples:
- mysql_real_escape_string() → mysql_real_escape_string_quote()
- mysql_real_escape_string() (for binary data) → mysql_hex_string()
Look for the error in your application logs:
CR_INSECURE_API_ERR (2062): Insecure API function call: 'mysql_real_escape_string'
Use instead: 'mysql_real_escape_string_quote'If the error involves mysql_real_escape_string(), verify whether NO_BACKSLASH_ESCAPES SQL mode is active on your server:
SELECT @@sql_mode;If the output includes NO_BACKSLASH_ESCAPES, this explains why mysql_real_escape_string() is rejected - it cannot safely escape strings when backslashes are not treated as escape characters.
Update your C code to use the safer mysql_real_escape_string_quote() function, which handles NO_BACKSLASH_ESCAPES correctly by accepting an additional quote character parameter.
Before (insecure):
char escaped[1024];
unsigned long escaped_len = mysql_real_escape_string(mysql, escaped, unescaped, strlen(unescaped));After (secure):
char escaped[1024];
unsigned long escaped_len = mysql_real_escape_string_quote(mysql, escaped, unescaped, strlen(unescaped), '\'');The last parameter specifies the quote character context (typically single quote \' or double quote \").
For binary data (BLOB, VARBINARY), use mysql_hex_string() instead of string escaping functions when NO_BACKSLASH_ESCAPES is enabled:
char hex_str[1024];
unsigned long hex_len = mysql_hex_string(hex_str, binary_data, binary_data_len);
// Use in query as hexadecimal literal
char query[2048];
sprintf(query, "INSERT INTO table (blob_column) VALUES (0x%s)", hex_str);This converts binary data to hexadecimal representation, which doesn't require escaping.
If the error relates to authentication functions, upgrade from deprecated mysql_old_password to mysql_native_password or newer authentication plugins.
Update user accounts:
-- Check current authentication plugin
SELECT user, host, plugin FROM mysql.user WHERE user = 'your_user';
-- Upgrade to native password authentication
ALTER USER 'your_user'@'localhost' IDENTIFIED WITH mysql_native_password BY 'new_password';
FLUSH PRIVILEGES;Then update your C client code to use the corresponding authentication methods.
After updating the API function calls, recompile your application against the MySQL C client library:
gcc -o myapp myapp.c -I/usr/include/mysql -L/usr/lib/mysql -lmysqlclientTest thoroughly with both NO_BACKSLASH_ESCAPES enabled and disabled:
-- Test with NO_BACKSLASH_ESCAPES
SET sql_mode = 'NO_BACKSLASH_ESCAPES';
-- Run your application tests
-- Test without NO_BACKSLASH_ESCAPES
SET sql_mode = '';
-- Run your application tests againVersion Compatibility: The CR_INSECURE_API_ERR error was introduced in MySQL 5.7.6 as part of enhanced security measures. If you're maintaining code that needs to support both older and newer MySQL versions, use conditional compilation or runtime version detection to choose the appropriate API function.
SQL Mode Considerations: The NO_BACKSLASH_ESCAPES mode is often enabled for ANSI SQL compliance or when migrating from databases like PostgreSQL. If you control the server configuration and don't require this mode, you could disable it as a workaround, but updating to secure API functions is the recommended long-term solution.
Prepared Statements Alternative: Consider migrating to prepared statements using mysql_stmt_prepare() and mysql_stmt_bind_param() instead of manual string escaping. Prepared statements eliminate the need for escaping entirely and provide better security against SQL injection:
MYSQL_STMT *stmt = mysql_stmt_init(mysql);
const char *query = "INSERT INTO users (name) VALUES (?)";
mysql_stmt_prepare(stmt, query, strlen(query));
MYSQL_BIND bind[1];
char name[100] = "O'Reilly";
bind[0].buffer_type = MYSQL_TYPE_STRING;
bind[0].buffer = name;
bind[0].buffer_length = strlen(name);
bind[0].is_null = 0;
mysql_stmt_bind_param(stmt, bind);
mysql_stmt_execute(stmt);Legacy Code Migration: If you're maintaining a large codebase, search for all instances of flagged functions and create a migration plan. The MySQL client library headers define the error constants in errmsg.h, which you can review to see all potentially affected functions.
ERROR 1064: You have an error in your SQL syntax
How to fix "ERROR 1064: You have an error in your SQL syntax" in MySQL
ERROR 1054: Unknown column in field list
Unknown column in field list
ER_WINDOW_RANGE_FRAME_NUMERIC_TYPE (3589): RANGE frame requires numeric ORDER BY expression
RANGE frame requires numeric ORDER BY expression in MySQL window functions
CR_ALREADY_CONNECTED (2058): Handle already connected
How to fix "CR_ALREADY_CONNECTED (2058): Handle already connected" in MySQL
ER_WINDOW_DUPLICATE_NAME (3591): Duplicate window name
How to fix ER_WINDOW_DUPLICATE_NAME (3591) in MySQL window functions