Overview
CVE-2026-4662 describes an SQL Injection vulnerability in the JetEngine WordPress plugin where an attacker can abuse an unauthenticated AJAX action to inject arbitrary SQL due to a missing HMAC binding for the filtered_query input and unsafe query construction. Specifically, the vulnerability arises when the filtered_query parameter is excluded from the HMAC signature validation, so attacker-controlled input bypasses security checks. Additionally, the plugin’s prepare_where_clause() path concatenates user-supplied operators into SQL statements without proper sanitization, enabling query modification and data exfiltration. This illustrates how signing and query construction must both be treated with strict input handling to prevent unauthorized access. Although this CVE targets PHP/WordPress, the underlying lessons apply broadly: do not trust client-supplied data, ensure all inputs are covered by integrity checks, and never concatenate untrusted values into SQL. In Go with Gin, injection variants emerge when you interpolate user data into SQL or fail to validate and bind inputs used in dynamic queries, and when you rely on signatures or tokens that do not cover all relevant parameters as demonstrated by CVE-2026-4662.
Code Fix Example
Go (Gin) API Security Remediation
package main
import (
"crypto/hmac"
"crypto/sha256"
"database/sql"
"encoding/hex"
"fmt"
"log"
"net/http"
"github.com/gin-gonic/gin"
_ "github.com/mattn/go-sqlite3"
)
func main() {
db, err := sql.Open("sqlite3", ":memory:")
if err != nil { log.Fatal(err) }
defer db.Close()
// initialize sample data
_, _ = db.Exec("CREATE TABLE users (id INTEGER PRIMARY KEY, name TEXT, email TEXT)")
_, _ = db.Exec("INSERT INTO users (name, email) VALUES ('alice','[email protected]'), ('bob','[email protected]')")
r := gin.Default()
r.GET("/vuln/search", func(c *gin.Context) { vulnerableQuery(c, db) })
r.GET("/fix/search", func(c *gin.Context) { fixedQuery(c, db) })
r.Run(":8080")
}
// Vulnerable pattern: susceptible to SQL injection via string interpolation
func vulnerableQuery(c *gin.Context, db *sql.DB) {
field := c.Query("field")
op := c.Query("op")
value := c.Query("value")
// WARNING: Do not interpolate user input directly into SQL.
sqlStmt := fmt.Sprintf("SELECT id, name FROM users WHERE %s %s '%s'", field, op, value)
rows, err := db.Query(sqlStmt)
if err != nil {
c.String(http.StatusInternalServerError, "query error")
return
}
defer rows.Close()
var results []string
for rows.Next() {
var id int
var name string
if err := rows.Scan(&id, &name); err != nil {
continue
}
results = append(results, fmt.Sprintf("%d:%s", id, name))
}
c.JSON(http.StatusOK, gin.H{"results": results})
}
// Fixed pattern: whitelist fields/operators and bind values using placeholders
func fixedQuery(c *gin.Context, db *sql.DB) {
field := c.Query("field")
op := c.Query("op")
value := c.Query("value")
// Whitelisting to prevent injection in dynamic SQL
allowedFields := map[string]bool{"name": true, "email": true}
allowedOps := map[string]bool{"=": true, "LIKE": true}
if !allowedFields[field] {
c.String(http.StatusBadRequest, "invalid field")
return
}
if !allowedOps[op] {
c.String(http.StatusBadRequest, "invalid operator")
return
}
// Bind value safely; field/op are validated against allowlists
sqlStmt := fmt.Sprintf("SELECT id, name FROM users WHERE %s %s ?", field, op)
rows, err := db.Query(sqlStmt, value)
if err != nil {
c.String(http.StatusInternalServerError, "query error")
return
}
defer rows.Close()
var results []string
for rows.Next() {
var id int
var name string
if err := rows.Scan(&id, &name); err != nil {
continue
}
results = append(results, fmt.Sprintf("%d:%s", id, name))
}
c.JSON(http.StatusOK, gin.H{"results": results})
}
// Optional: verify that the provided HMAC matches the inputs used for the request
func verifySignature(params map[string]string, provided string) bool {
secret := []byte("change-me-to-secret")
msg := params["field"] + "|" + params["op"] + "|" + params["value"] + "|" + params["ts"]
mac := hmac.New(sha256.New, secret)
mac.Write([]byte(msg))
expected := hex.EncodeToString(mac.Sum(nil))
return hmac.Equal([]byte(provided), []byte(expected))
}