diff --git a/Caddyfile b/Caddyfile
index 06dbb83..45cc567 100644
--- a/Caddyfile
+++ b/Caddyfile
@@ -12,6 +12,13 @@ http://document.hyungi.net {
     # 명시 Content-Type match — 기본 match 의 text/* 는 text/event-stream 까지 포함해
     # SSE(/api/eid/chat)의 첫 ~512B 를 gzip 버퍼링함. SSE 제외, 기존 압축 대상은 보존.
     # (응답 매처는 header <필드> <값> 한 쌍씩 — 여러 줄 = OR. 한 줄 다중 값은 파싱 에러)
+    # 2026-06-20 보안 헤더 (M: 클릭재킹·MIME 스니핑 방어). HSTS 는 TLS 종단 edge(home-caddy) 소관.
+    header {
+        X-Content-Type-Options nosniff
+        X-Frame-Options SAMEORIGIN
+        Referrer-Policy strict-origin-when-cross-origin
+        -Server
+    }
     encode {
         gzip
         match {
diff --git a/app/api/documents.py b/app/api/documents.py
index 9732489..d3af888 100644
--- a/app/api/documents.py
+++ b/app/api/documents.py
@@ -1277,6 +1277,14 @@ async def update_document(
         if val is not None and val not in ("business", "knowledge"):
             raise HTTPException(status_code=400, detail="doc_purpose는 business 또는 knowledge만 가능")
 
+    # edit_url SSRF 가드 (2026-06-20 M1): 내부/메타데이터 주소 후속 fetch 차단 (news.py 동형 검증)
+    if update_data.get("edit_url"):
+        from core.url_validator import validate_feed_url
+        try:
+            await asyncio.to_thread(validate_feed_url, update_data["edit_url"])
+        except Exception as e:
+            raise HTTPException(status_code=400, detail=f"edit_url 검증 실패: {e}")
+
     for field, value in update_data.items():
         setattr(doc, field, value)
     doc.updated_at = datetime.now(timezone.utc)
diff --git a/app/api/library.py b/app/api/library.py
index a0137d7..26207ab 100644
--- a/app/api/library.py
+++ b/app/api/library.py
@@ -9,7 +9,7 @@ from sqlalchemy import func, select
 from sqlalchemy import text as sql_text
 from sqlalchemy.ext.asyncio import AsyncSession
 
-from core.auth import get_current_user
+from core.auth import get_current_user, require_admin
 from core.database import get_session
 from core.library import LIBRARY_PREFIX, MAX_DEPTH, normalize_library_path
 from models.category import LibraryCategory
@@ -78,7 +78,7 @@ async def list_categories(
 @router.post("/categories", response_model=CategoryResponse, status_code=201)
 async def create_category(
     body: CategoryCreate,
-    user: Annotated[User, Depends(get_current_user)],
+    user: Annotated[User, Depends(require_admin)],
     session: Annotated[AsyncSession, Depends(get_session)],
 ):
     """카테고리 생성 (조상 자동 생성 포함)"""
@@ -133,7 +133,7 @@ async def create_category(
 @router.patch("/categories", response_model=CategoryResponse)
 async def rename_category(
     body: CategoryRename,
-    user: Annotated[User, Depends(get_current_user)],
+    user: Annotated[User, Depends(require_admin)],
     session: Annotated[AsyncSession, Depends(get_session)],
 ):
     """카테고리 이름 변경 (leaf only, path 기반 식별)"""
@@ -214,7 +214,7 @@ async def rename_category(
 @router.delete("/categories", status_code=204)
 async def delete_category(
     path: str = Query(..., description="삭제할 카테고리 경로"),
-    user: Annotated[User, Depends(get_current_user)] = None,
+    user: Annotated[User, Depends(require_admin)] = None,
     session: Annotated[AsyncSession, Depends(get_session)] = None,
 ):
     """카테고리 삭제 (leaf only, 문서 없는 경우만)"""
@@ -410,7 +410,7 @@ async def get_facet_values(
 @router.post("/facets", response_model=FacetValueResponse, status_code=201)
 async def add_facet_value(
     body: FacetValueResponse,
-    user: Annotated[User, Depends(get_current_user)],
+    user: Annotated[User, Depends(require_admin)],
     session: Annotated[AsyncSession, Depends(get_session)],
 ):
     """facet 사전에 새 값 추가"""
diff --git a/docker-compose.yml b/docker-compose.yml
index 4e692db..dccdf1a 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -263,7 +263,7 @@ services:
   caddy:
     image: caddy:2
     ports:
-      - "8080:80"
+      - "127.0.0.1:8080:80"  # 2026-06-20: LAN 우회 차단 (실 ingress=home-caddy→caddy:80 도커망)
     volumes:
       - ./Caddyfile:/etc/caddy/Caddyfile
       - caddy_data:/data
diff --git a/scripts/audit_study_question_markdown.py b/scripts/audit_study_question_markdown.py
index c4ffe04..58810ef 100644
--- a/scripts/audit_study_question_markdown.py
+++ b/scripts/audit_study_question_markdown.py
@@ -289,7 +289,7 @@ async def run(topic_id: int, exam_round: str, apply: bool, abort_threshold: int)
         host="postgres",
         port=5432,
         user="pkm",
-        password="uW38friypljVS0X2ULoMnw",
+        password=os.environ["POSTGRES_PASSWORD"],
         database="pkm",
     )
     try:
diff --git a/scripts/strip_outer_fences.py b/scripts/strip_outer_fences.py
index 9d3da1a..12bf614 100644
--- a/scripts/strip_outer_fences.py
+++ b/scripts/strip_outer_fences.py
@@ -16,6 +16,7 @@ dry-run 먼저 출력 (각 필드 N건). 그 다음 --apply 옵션으로 UPDATE.
 from __future__ import annotations
 
 import asyncio
+import os
 import re
 import sys
 
@@ -99,7 +100,7 @@ async def main() -> None:
         host="postgres",
         port=5432,
         user="pkm",
-        password="uW38friypljVS0X2ULoMnw",
+        password=os.environ["POSTGRES_PASSWORD"],
         database="pkm",
     )
     try: