Overview
CVE-2026-25715 describes a vulnerability where an administrator could set the user credentials (username and password) to blank values in a device's web management interface. Once applied, authentication would succeed with empty credentials, effectively granting full administrative access over web management and related services. This is tied to CWE-521: Weak Password, where missing or blank credentials undermine authentication and open the door to privilege escalation. In a Go (Gin) context, a similar pattern can emerge if an app reads credentials from environment/config and compares against the provided input without validating non-empty values or without hashing the stored password. An attacker could supply blank or default credentials to gain admin-like access and then perform actions on sensitive resources. The real-world impact is substantial: once authenticated, an attacker can modify critical settings, exfiltrate data, or disable security controls, and if object-level authorization is not enforced, they may access or manipulate any resource tied to that account.
This vulnerability class is particularly dangerous when combined with broken object property level authorization: if authentication succeeds but per-object checks are not performed, an attacker bearing valid (even if blank) credentials can access or modify resources beyond their intended scope. In Go with Gin, this manifests as login logic that accepts empty credentials or stores credentials insecurely (e.g., plaintext in config) and resource handlers that trust a session or header without validating ownership or role. The result is an attacker who can authenticate and then perform privileged actions on any object (for example, device configurations, users, or administrative settings) without proper authorization checks. The remediation is to enforce strict authentication (non-empty, hashed passwords) and to implement robust object-level authorization so that every resource access validates ownership or role before returning data or performing operations.
Code Fix Example
Go (Gin) API Security Remediation
package main
import (
"log"
"net/http"
"os"
"github.com/gin-gonic/gin"
"golang.org/x/crypto/bcrypt"
)
type Credentials struct {
Username string `json:"username"`
Password string `json:"password"`
}
var adminUser string
var adminPassHash []byte
func main() {
// Load credentials from environment
adminUser = os.Getenv("ADMIN_USER")
plainPass := os.Getenv("ADMIN_PASS")
if adminUser == "" || plainPass == "" {
log.Fatal("ADMIN_USER and ADMIN_PASS must be set and non-empty")
}
hash, err := bcrypt.GenerateFromPassword([]byte(plainPass), bcrypt.DefaultCost)
if err != nil {
log.Fatalf("failed to hash admin password: %v", err)
}
adminPassHash = hash
r := gin.Default()
// Vulnerable pattern (for illustration): validates only by direct string compare
r.POST("/vulnerable/login", func(c *gin.Context) {
var cred Credentials
if err := c.BindJSON(&cred); err != nil {
c.JSON(http.StatusBadRequest, gin.H{"error": "bad request"})
return
}
// Vulnerable: if ADMIN_USER or ADMIN_PASS are blank in env, or if credentials match,
// login succeeds. This mirrors the CVE where empty credentials could bypass auth.
if cred.Username == adminUser && cred.Password == os.Getenv("ADMIN_PASS") {
c.JSON(http.StatusOK, gin.H{"status": "admin login (vulnerable)"})
return
}
c.JSON(http.StatusUnauthorized, gin.H{"status": "unauthorized"})
})
// Secure pattern: non-empty checks and bcrypt-based password verification
r.POST("/secure/login", func(c *gin.Context) {
var cred Credentials
if err := c.BindJSON(&cred); err != nil {
c.JSON(http.StatusBadRequest, gin.H{"error": "bad request"})
return
}
if adminUser == "" {
c.JSON(http.StatusInternalServerError, gin.H{"error": "server misconfiguration"})
return
}
if cred.Username != adminUser {
c.JSON(http.StatusUnauthorized, gin.H{"status": "unauthorized"})
return
}
if err := bcrypt.CompareHashAndPassword(adminPassHash, []byte(cred.Password)); err != nil {
c.JSON(http.StatusUnauthorized, gin.H{"status": "unauthorized"})
return
}
c.JSON(http.StatusOK, gin.H{"status": "admin login (secure)"})
})
// Example of object-level authorization: only the resource owner can access the object
// We simulate a small in-memory map of owners for demonstration purposes.
resourceOwners := map[string]string{
"device1": "alice",
"device2": "bob",
}
// Vulnerable object access (no ownership check)
r.GET("/device/:id/config", func(c *gin.Context) {
user := c.GetHeader("X-USER")
if user == "" {
c.JSON(http.StatusUnauthorized, gin.H{"status": "unauthorized"})
return
}
id := c.Param("id")
// No ownership check here - this is intentionally vulnerable for demonstration
c.JSON(http.StatusOK, gin.H{"device": id, "config": "{...}"})
})
// Secure object access with ownership check
r.GET("/secure/device/:id/config", func(c *gin.Context) {
user := c.GetHeader("X-USER")
if user == "" {
c.JSON(http.StatusUnauthorized, gin.H{"status": "unauthorized"})
return
}
id := c.Param("id")
owner, ok := resourceOwners[id]
if !ok {
c.JSON(http.StatusNotFound, gin.H{"status": "not found"})
return
}
if owner != user {
c.JSON(http.StatusForbidden, gin.H{"status": "forbidden"})
return
}
c.JSON(http.StatusOK, gin.H{"device": id, "config": "{...}"})
})
_ = r.Run(":8080")
}