Overview
Broken Object Level Authorization (BOLA) occurs when an application authenticates a user but fails to enforce per-object access checks, allowing access to resources the user should not own. The real-world CVE-2026-23902 in Apache DolphinScheduler demonstrates this risk: authenticated users with system login permissions could operate on tenants that are not defined on the platform during workflow execution. This kind of flaw illustrates how object-level protections can be missing or misconfigured in multi-tenant systems, leading to cross-tenant data exposure or unauthorized operations. Properly enforcing resource ownership and tenant scoping is essential to prevent these issues in Go applications using Gin.
In the DolphinScheduler case, an attacker could manipulate the workflow execution path to act on tenants not assigned to their account, effectively bypassing tenant-level boundaries after login. The CVE was mitigated by upgrading to version 3.4.1, which adds proper per-tenant checks before workflow actions. This guide translates that risk into the Go (Gin) context and shows concrete steps to enforce object-level authorization in Go services.
In Go applications using the Gin framework, BOLA can manifest when handlers fetch resources by ID and return them after only authenticating the user or checking a general role, without verifying the object's owner or tenant. Attackers can present valid, authenticated requests that reference other users’ objects, exposing data or capabilities that should be restricted. The remediation pattern is to tie every data access to explicit, per-resource authorization checks (ownership/tenant membership) and to centralize this logic in reusable middleware or helpers.
Remediation should emphasize per-resource checks, tenant scoping, and test coverage to prevent regressions across endpoints that touch sensitive objects.
Affected Versions
DolphinScheduler < 3.4.1
Code Fix Example
Go (Gin) API Security Remediation
package main
import (
"net/http"
"strings"
"github.com/gin-gonic/gin"
)
type User struct { ID string; Tenants []string }
type Resource struct { ID string; Tenant string }
var resources = map[string]*Resource{
"r1": &Resource{ID: "r1", Tenant: "tenantA"},
"r2": &Resource{ID: "r2", Tenant: "tenantB"},
}
func main() {
r := gin.Default()
r.Use(mockAuthMiddleware())
// Vulnerable: lacks object-level authorization check
r.GET("/vuln/resource/:id", func(c *gin.Context) {
u := getUser(c)
if u == nil { c.JSON(http.StatusUnauthorized, gin.H{"error":"unauthorized"}); return }
id := c.Param("id")
res := resources[id]
if res == nil { c.JSON(http.StatusNotFound, gin.H{"error":"not found"}); return }
// Vulnerable: returns resource without verifying ownership/tenant
c.JSON(http.StatusOK, res)
})
// Fixed: enforce per-resource access control
r.GET("/fixed/resource/:id", func(c *gin.Context) {
u := getUser(c)
if u == nil { c.JSON(http.StatusUnauthorized, gin.H{"error":"unauthorized"}); return }
id := c.Param("id")
res := resources[id]
if res == nil { c.JSON(http.StatusNotFound, gin.H{"error":"not found"}); return }
if !userHasAccessToTenant(u, res.Tenant) {
c.JSON(http.StatusForbidden, gin.H{"error":"forbidden"})
return
}
c.JSON(http.StatusOK, res)
})
r.Run()
}
func getUser(c *gin.Context) *User {
if v, ok := c.Get("user"); ok {
return v.(*User)
}
return nil
}
func mockAuthMiddleware() gin.HandlerFunc {
return func(c *gin.Context) {
id := c.GetHeader("X-User-ID")
tenants := []string{}
if v := c.GetHeader("X-User-Tenants"); v != "" {
for _, t := range strings.Split(v, ",") {
tenants = append(tenants, strings.TrimSpace(t))
}
}
if id != "" {
c.Set("user", &User{ID: id, Tenants: tenants})
}
c.Next()
}
}
func userHasAccessToTenant(u *User, t string) bool {
for _, x := range u.Tenants {
if x == t { return true }
}
return false
}