diff --git a/backend/routers/network.py b/backend/routers/network.py
index 24832a8..bcc6492 100644
--- a/backend/routers/network.py
+++ b/backend/routers/network.py
@@ -46,6 +46,17 @@ def _require_nmcli():
         raise HTTPException(503, "NetworkManager (nmcli) not available on this system")
 
 
+def _safe_env():
+    """Build environment with full PATH for nmcli commands."""
+    env = {**os.environ, "LC_ALL": "C"}
+    path = env.get("PATH", "")
+    for p in ("/usr/bin", "/usr/sbin", "/bin", "/sbin"):
+        if p not in path:
+            path = p + ":" + path
+    env["PATH"] = path
+    return env
+
+
 async def _nmcli(*args: str, timeout: float = 30) -> str:
     """Run nmcli with C locale, return stdout. Raise HTTPException on failure."""
     _require_nmcli()
@@ -54,7 +65,7 @@ async def _nmcli(*args: str, timeout: float = 30) -> str:
         *cmd,
         stdout=asyncio.subprocess.PIPE,
         stderr=asyncio.subprocess.PIPE,
-        env={**os.environ, "LC_ALL": "C"},
+        env=_safe_env(),
     )
     try:
         stdout, stderr = await asyncio.wait_for(proc.communicate(), timeout=timeout)
diff --git a/backend/routers/packages.py b/backend/routers/packages.py
index 8a6fc72..28654bd 100644
--- a/backend/routers/packages.py
+++ b/backend/routers/packages.py
@@ -16,7 +16,19 @@ router = APIRouter(prefix="/api/packages", tags=["packages"])
 # Guard
 # ---------------------------------------------------------------------------
 
-_HAS_APT = bool(shutil.which("apt-cache"))
+def _find_apt():
+    """Find apt-cache binary, checking common paths if PATH is restricted."""
+    found = shutil.which("apt-cache")
+    if found:
+        return True
+    # systemd services may have a minimal PATH — check directly
+    for p in ("/usr/bin/apt-cache", "/usr/sbin/apt-cache"):
+        if os.path.isfile(p) and os.access(p, os.X_OK):
+            return True
+    return False
+
+
+_HAS_APT = _find_apt()
 
 
 def _require_apt():
@@ -38,6 +50,18 @@ def _validate_name(name: str) -> str:
     return name
 
 
+def _safe_env():
+    """Build environment with full PATH for apt/dpkg commands."""
+    env = {**os.environ, "LC_ALL": "C", "DEBIAN_FRONTEND": "noninteractive"}
+    # Ensure standard paths are included (systemd may use minimal PATH)
+    path = env.get("PATH", "")
+    for p in ("/usr/bin", "/usr/sbin", "/bin", "/sbin"):
+        if p not in path:
+            path = p + ":" + path
+    env["PATH"] = path
+    return env
+
+
 async def _apt(*args: str, timeout: float = 30) -> str:
     """Run an apt/dpkg command and return stdout."""
     _require_apt()
@@ -46,7 +70,7 @@ async def _apt(*args: str, timeout: float = 30) -> str:
         *cmd,
         stdout=asyncio.subprocess.PIPE,
         stderr=asyncio.subprocess.PIPE,
-        env={**os.environ, "LC_ALL": "C", "DEBIAN_FRONTEND": "noninteractive"},
+        env=_safe_env(),
     )
     try:
         stdout, stderr = await asyncio.wait_for(proc.communicate(), timeout=timeout)
@@ -68,7 +92,7 @@ async def _apt_nofail(*args: str, timeout: float = 30) -> tuple[int, str, str]:
         *cmd,
         stdout=asyncio.subprocess.PIPE,
         stderr=asyncio.subprocess.PIPE,
-        env={**os.environ, "LC_ALL": "C", "DEBIAN_FRONTEND": "noninteractive"},
+        env=_safe_env(),
     )
     try:
         stdout, stderr = await asyncio.wait_for(proc.communicate(), timeout=timeout)
diff --git a/backend/routers/updates.py b/backend/routers/updates.py
index f1e6946..8fb9541 100644
--- a/backend/routers/updates.py
+++ b/backend/routers/updates.py
@@ -30,6 +30,17 @@ def _require_git():
 # Helpers
 # ---------------------------------------------------------------------------
 
+def _safe_env():
+    """Build environment with full PATH for git commands."""
+    env = {**os.environ, "LC_ALL": "C"}
+    path = env.get("PATH", "")
+    for p in ("/usr/bin", "/usr/sbin", "/bin", "/sbin"):
+        if p not in path:
+            path = p + ":" + path
+    env["PATH"] = path
+    return env
+
+
 async def _git(*args: str, timeout: float = 30) -> str:
     """Run a git command in the Atlus install directory."""
     _require_git()
@@ -38,7 +49,7 @@ async def _git(*args: str, timeout: float = 30) -> str:
         *cmd,
         stdout=asyncio.subprocess.PIPE,
         stderr=asyncio.subprocess.PIPE,
-        env={**os.environ, "LC_ALL": "C"},
+        env=_safe_env(),
     )
     try:
         stdout, stderr = await asyncio.wait_for(proc.communicate(), timeout=timeout)
@@ -60,7 +71,7 @@ async def _git_nofail(*args: str, timeout: float = 30) -> tuple[int, str]:
         *cmd,
         stdout=asyncio.subprocess.PIPE,
         stderr=asyncio.subprocess.PIPE,
-        env={**os.environ, "LC_ALL": "C"},
+        env=_safe_env(),
     )
     try:
         stdout, stderr = await asyncio.wait_for(proc.communicate(), timeout=timeout)