diff --git a/.jules/sentinel.md b/.jules/sentinel.md
index e795cb9d..dbb6faf7 100644
--- a/.jules/sentinel.md
+++ b/.jules/sentinel.md
@@ -32,3 +32,8 @@
 **Vulnerability:** The document hashing routine in `DefaultDocumentConversionService` processed file streams without enforcing any maximum size limit on the bytes read. An attacker could exploit this by uploading a maliciously large stream (or exploiting a compression bomb if unzipping), exhausting system memory, CPU, or disk space (DoS).
 **Learning:** Checking the declared file size (e.g., `file.getSize()`) in initial validation is not always sufficient if the input stream itself can be spoofed or dynamically expanded during reading. The actual bytes read must be verified against bounds continuously.
 **Prevention:** Always enforce a strict, configurable size limit (e.g., `ConversionProperties.maxUploadSizeBytes`) within the `while` loop that reads from untrusted input streams. Track `totalRead` and throw an exception immediately if the limit is exceeded.
+
+## 2026-07-30 - Admin endpoint 인증 누락 해결
+**Vulnerability:** `/api/v1/admin/*` 경로의 API 엔드포인트들에 인증 및 권한 확인(`TenantAccessService.require`)이 누락되어 있어, 인가되지 않은 사용자가 관리자 기능을 사용할 수 있는 심각한 보안 취약점이 있었습니다.
+**Learning:** 새로운 API 컨트롤러(`AdminController`)를 추가할 때 전역적인 보안 필터가 아닌 컨트롤러 수준에서 권한 검증을 강제하고 있었으므로, 새 엔드포인트에 실수로 권한 검증 코드를 누락하기 쉬운 구조였습니다.
+**Prevention:** 모든 새로운 엔드포인트 추가 시 반드시 `TenantAccessService`를 주입받아 적절한 `TenantPermissions` 권한을 검증하는지 확인해야 하며, 이를 자동화된 테스트나 리뷰 프로세스에서 필수적으로 점검해야 합니다.
diff --git a/src/main/java/com/clearfolio/viewer/auth/TenantPermissions.java b/src/main/java/com/clearfolio/viewer/auth/TenantPermissions.java
index ced5e6a3..97d27e8f 100644
--- a/src/main/java/com/clearfolio/viewer/auth/TenantPermissions.java
+++ b/src/main/java/com/clearfolio/viewer/auth/TenantPermissions.java
@@ -50,6 +50,11 @@ public final class TenantPermissions {
      */
     public static final String ANALYTICS_READ = "analytics:read";
 
+    /**
+     * Permission required to manage admin operations.
+     */
+    public static final String ADMIN_MANAGE = "admin:manage";
+
     private TenantPermissions() {
     }
 }
diff --git a/src/main/java/com/clearfolio/viewer/controller/AdminController.java b/src/main/java/com/clearfolio/viewer/controller/AdminController.java
index 412d4eb8..15a4653e 100644
--- a/src/main/java/com/clearfolio/viewer/controller/AdminController.java
+++ b/src/main/java/com/clearfolio/viewer/controller/AdminController.java
@@ -9,12 +9,16 @@
 import org.springframework.web.bind.annotation.DeleteMapping;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.http.HttpHeaders;
 import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestHeader;
 import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.bind.annotation.RestController;
 import org.springframework.web.server.ResponseStatusException;
 
 import com.clearfolio.viewer.api.AdminJobListResponse;
+import com.clearfolio.viewer.auth.TenantAccessService;
+import com.clearfolio.viewer.auth.TenantPermissions;
 import com.clearfolio.viewer.model.ConversionJob;
 import com.clearfolio.viewer.service.DocumentConversionService;
 import com.clearfolio.viewer.service.RetryDeadLetterResult;
@@ -25,25 +29,41 @@
 @RestController
 public class AdminController {
 
+    /**
+     * Conversion service for document processing.
+     */
     private final DocumentConversionService conversionService;
 
+    /**
+     * Service for tenant and permission enforcement.
+     */
+    private final TenantAccessService tenantAccessService;
+
     /**
      * Creates a controller for admin operations.
      *
-     * @param conversionService conversion service
+     * @param conversionSvc conversion service
+     * @param tenantAccessSvc access service
      */
-    public AdminController(DocumentConversionService conversionService) {
-        this.conversionService = conversionService;
+    public AdminController(
+            final DocumentConversionService conversionSvc,
+            final TenantAccessService tenantAccessSvc) {
+        this.conversionService = conversionSvc;
+        this.tenantAccessService = tenantAccessSvc;
     }
 
     /**
      * Retrieves all conversion jobs, optionally filtered by dead-letter status.
      *
      * @param deadLettered optional filter for dead-lettered jobs
+     * @param headers request headers
      * @return list of conversion jobs
      */
     @GetMapping("/api/v1/admin/convert/jobs")
-    public AdminJobListResponse getAllJobs(@RequestParam(required = false) Boolean deadLettered) {
+    public AdminJobListResponse getAllJobs(
+            @RequestParam(required = false) final Boolean deadLettered,
+            @RequestHeader final HttpHeaders headers) {
+        tenantAccessService.require(headers, TenantPermissions.ADMIN_MANAGE);
         Iterable<ConversionJob> allJobs = conversionService.getAllJobs();
 
         if (deadLettered == null) {
@@ -63,10 +83,14 @@ public AdminJobListResponse getAllJobs(@RequestParam(required = false) Boolean d
      * Deletes a conversion job.
      *
      * @param jobId conversion job identifier
+     * @param headers request headers
      * @return no content on success
      */
     @DeleteMapping("/api/v1/admin/convert/jobs/{jobId}")
-    public ResponseEntity<Void> deleteJob(@PathVariable UUID jobId) {
+    public ResponseEntity<Void> deleteJob(
+            @PathVariable final UUID jobId,
+            @RequestHeader final HttpHeaders headers) {
+        tenantAccessService.require(headers, TenantPermissions.ADMIN_MANAGE);
         conversionService.deleteJob(jobId);
         return ResponseEntity.noContent().build();
     }
@@ -75,16 +99,23 @@ public ResponseEntity<Void> deleteJob(@PathVariable UUID jobId) {
      * Retries a dead-lettered conversion job.
      *
      * @param jobId conversion job identifier
+     * @param headers request headers
      * @return accepted response on success
      */
     @PostMapping("/api/v1/admin/convert/jobs/{jobId}/retry")
-    public ResponseEntity<Void> retryDeadLettered(@PathVariable UUID jobId) {
-        RetryDeadLetterResult result = conversionService.retryDeadLettered(jobId, "admin");
+    public ResponseEntity<Void> retryDeadLettered(
+            @PathVariable final UUID jobId,
+            @RequestHeader final HttpHeaders headers) {
+        tenantAccessService.require(headers, TenantPermissions.ADMIN_MANAGE);
+        RetryDeadLetterResult result =
+                conversionService.retryDeadLettered(jobId, "admin");
         if (result == RetryDeadLetterResult.NOT_FOUND) {
-            throw new ResponseStatusException(HttpStatus.NOT_FOUND, "job not found");
+            throw new ResponseStatusException(
+                    HttpStatus.NOT_FOUND, "job not found");
         }
         if (result == RetryDeadLetterResult.NOT_ELIGIBLE) {
-            throw new ResponseStatusException(HttpStatus.CONFLICT, "job is not eligible for retry");
+            throw new ResponseStatusException(
+                    HttpStatus.CONFLICT, "job is not eligible for retry");
         }
         return ResponseEntity.accepted().build();
     }
diff --git a/src/test/java/com/clearfolio/viewer/controller/AdminControllerTest.java b/src/test/java/com/clearfolio/viewer/controller/AdminControllerTest.java
index ad63a801..78308eb6 100644
--- a/src/test/java/com/clearfolio/viewer/controller/AdminControllerTest.java
+++ b/src/test/java/com/clearfolio/viewer/controller/AdminControllerTest.java
@@ -1,15 +1,21 @@
 package com.clearfolio.viewer.controller;
 
 import static org.mockito.Mockito.mock;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Mockito.when;
 
 import java.util.Arrays;
+import java.util.Set;
 import java.util.UUID;
 
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.springframework.test.web.reactive.server.WebTestClient;
 
+import com.clearfolio.viewer.auth.TenantAccessService;
+import com.clearfolio.viewer.auth.TenantContext;
+import com.clearfolio.viewer.auth.TenantPermissions;
 import com.clearfolio.viewer.model.ConversionJob;
 import com.clearfolio.viewer.service.DocumentConversionService;
 import com.clearfolio.viewer.service.RetryDeadLetterResult;
@@ -17,13 +23,19 @@
 class AdminControllerTest {
 
     private DocumentConversionService conversionService;
+    private TenantAccessService tenantAccessService;
     private WebTestClient webTestClient;
     private AdminController controller;
 
     @BeforeEach
     void setUp() {
         conversionService = mock(DocumentConversionService.class);
-        controller = new AdminController(conversionService);
+        tenantAccessService = mock(TenantAccessService.class);
+
+        TenantContext dummyContext = new TenantContext("tenant", "subject", Set.of(TenantPermissions.ADMIN_MANAGE));
+        when(tenantAccessService.require(any(), eq(TenantPermissions.ADMIN_MANAGE))).thenReturn(dummyContext);
+
+        controller = new AdminController(conversionService, tenantAccessService);
         webTestClient = WebTestClient.bindToController(controller)
                 .controllerAdvice(new ApiExceptionHandler())
                 .build();