How to fix CR_INSECURE_API_ERR (2062): Insecure API function call in MySQL

MySQLINTERMEDIATEMEDIUMUpdated Dec 22, 2025· 162 views

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.

Quick fix

Fixes 2062

CR_INSECURE_API_ERR (2062): Insecure API function call: 'mysql_real_escape_string'
Use instead: 'mysql_real_escape_string_quote'
  1. Identify the specific insecure function being called
  2. Check if NO_BACKSLASH_ESCAPES mode is enabled
  3. Replace mysql_real_escape_string() with mysql_real_escape_string_quote()
  4. Use mysql_hex_string() for binary data
mysql — error
CR_INSECURE_API_ERR (2062): Insecure API function call: 'mysql_real_escape_string'
Use instead: 'mysql_real_escape_string_quote'
CR_INSECURE_API_ERR (2062): Insecure API function call

What this error means

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.

Typical symptoms

  • Connection or query operations fail with error code 2062
  • Error message includes "Insecure API function call" with function names
  • Application works on older MySQL versions but fails on MySQL 5.7.6+
  • String escaping functions return errors when NO_BACKSLASH_ESCAPES is enabled
  • Legacy C API code fails after MySQL server upgrade

Common causes

  1. Using mysql_real_escape_string() when NO_BACKSLASH_ESCAPES SQL mode is enabled
  2. Calling deprecated authentication functions like mysql_old_password
  3. Using legacy string handling functions that have safer alternatives
  4. Application code written for pre-MySQL 5.7.6 versions not updated
  5. MySQL C client library detecting insecure function usage patterns

How to fix "CR_INSECURE_API_ERR (2062): Insecure API function call"

1Identify the specific insecure function being called

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:

bash
CR_INSECURE_API_ERR (2062): Insecure API function call: 'mysql_real_escape_string'
Use instead: 'mysql_real_escape_string_quote'
2Check if NO_BACKSLASH_ESCAPES mode is enabled

If the error involves mysql_real_escape_string(), verify whether NO_BACKSLASH_ESCAPES SQL mode is active on your server:

sql
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.

3Replace mysql_real_escape_string() with mysql_real_escape_string_quote()

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):

c
char escaped[1024];
unsigned long escaped_len = mysql_real_escape_string(mysql, escaped, unescaped, strlen(unescaped));

After (secure):

c
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 \").

4Use mysql_hex_string() for binary data

For binary data (BLOB, VARBINARY), use mysql_hex_string() instead of string escaping functions when NO_BACKSLASH_ESCAPES is enabled:

c
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.

5Update authentication plugin usage

If the error relates to authentication functions, upgrade from deprecated mysql_old_password to mysql_native_password or newer authentication plugins.

Update user accounts:

sql
-- 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.

6Recompile and test your application

After updating the API function calls, recompile your application against the MySQL C client library:

bash
gcc -o myapp myapp.c -I/usr/include/mysql -L/usr/lib/mysql -lmysqlclient

Test thoroughly with both NO_BACKSLASH_ESCAPES enabled and disabled:

sql
-- 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 again

Advanced notes

Version 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:

c
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.

Frequently asked questions

What does "2062" mean?
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.
How do I fix "2062"?
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.
What causes "2062"?
Using mysql_real_escape_string() when NO_BACKSLASH_ESCAPES SQL mode is enabled Calling deprecated authentication functions like mysql_old_password Using legacy string handling functions that have safer alternatives
Is the "2062" error serious?
It is a medium-severity error — more of a blocker than a risk. The steps above resolve it.

Official resources & further reading