Overview
CVE-2026-6189 highlights a remote SQL injection in SourceCodester Pharmacy Sales and Inventory System 1.0 where an attacker manipulates the Username parameter in /ajax.php?action=login to alter the query and gain unauthorized access or exfiltrate data. This maps to CWEs 74 and 89 (SQL Injection). In Go applications using Gin, similar risks exist when login handlers concatenate user input into SQL strings instead of using parameterized queries, enabling attackers to modify the intended query logic. If such patterns are exploited in Go services, attackers can bypass authentication, enumerate data, or escalate privileges. The vulnerability demonstrates why input handling and query construction must treat user input as untrusted and always rely on safe query practices. Cross-reference to CVE-2026-6189 underscores the real-world impact of this class of vulnerability and the need for strict mitigation in any stack, including Go/Gin.
Code Fix Example
Go (Gin) API Security Remediation
package main
import (
"database/sql"
"log"
"net/http"
"github.com/gin-gonic/gin"
_ "github.com/go-sql-driver/mysql"
)
var db *sql.DB
func main() {
dsn := `user:pass@tcp(127.0.0.1:3306)/shop`
var err error
db, err = sql.Open("mysql", dsn)
if err != nil { log.Fatal(err) }
defer db.Close()
r := gin.Default()
// Vulnerable login endpoint (for demonstration only)
r.POST("/login-vuln", func(c *gin.Context) {
username := c.PostForm("username")
password := c.PostForm("password")
// Vulnerable: direct string concatenation can lead to SQL injection
query := "SELECT id FROM users WHERE username = '" + username + "' AND password = '" + password + "'"
row := db.QueryRow(query)
var id int
if err := row.Scan(&id); err != nil {
c.JSON(http.StatusUnauthorized, gin.H{"error": "invalid credentials"})
return
}
c.JSON(http.StatusOK, gin.H{"id": id})
})
// Secure login endpoint (safe pattern)
r.POST("/login-secure", func(c *gin.Context) {
username := c.PostForm("username")
password := c.PostForm("password")
// Secure: parameterized query to prevent injection
row := db.QueryRow("SELECT id FROM users WHERE username = ? AND password = ?", username, password)
var id int
if err := row.Scan(&id); err != nil {
c.JSON(http.StatusUnauthorized, gin.H{"error": "invalid credentials"})
return
}
c.JSON(http.StatusOK, gin.H{"id": id})
})
r.Run()
}