diff --git a/weed/server/filer_jwt_test.go b/weed/server/filer_jwt_test.go
index bc9709c27..b66c085dd 100644
--- a/weed/server/filer_jwt_test.go
+++ b/weed/server/filer_jwt_test.go
@@ -137,6 +137,54 @@ func TestFilerServer_maybeCheckJwtAuthorization_Scoped(t *testing.T) {
 			isWrite:          false,
 			expectAuthorized: true,
 		},
+		{
+			name:             "tenant prefix does not match sibling tenant",
+			token:            genToken([]string{"/tenant1"}, nil),
+			method:           "GET",
+			path:             "/tenant1234/secret",
+			isWrite:          false,
+			expectAuthorized: false,
+		},
+		{
+			name:             "tenant prefix does not match dashed sibling",
+			token:            genToken([]string{"/tenant1"}, nil),
+			method:           "GET",
+			path:             "/tenant1-old/secret",
+			isWrite:          false,
+			expectAuthorized: false,
+		},
+		{
+			name:             "tenant prefix matches own subtree",
+			token:            genToken([]string{"/tenant1"}, nil),
+			method:           "GET",
+			path:             "/tenant1/ok.txt",
+			isWrite:          false,
+			expectAuthorized: true,
+		},
+		{
+			name:             "tenant prefix with trailing slash matches own subtree",
+			token:            genToken([]string{"/tenant1/"}, nil),
+			method:           "GET",
+			path:             "/tenant1/ok.txt",
+			isWrite:          false,
+			expectAuthorized: true,
+		},
+		{
+			name:             "root prefix matches anywhere",
+			token:            genToken([]string{"/"}, nil),
+			method:           "GET",
+			path:             "/tenant1234/secret",
+			isWrite:          false,
+			expectAuthorized: true,
+		},
+		{
+			name:             "dot-dot cannot escape allowed subtree",
+			token:            genToken([]string{"/tenant1"}, nil),
+			method:           "GET",
+			path:             "/tenant1/../tenant2/secret",
+			isWrite:          false,
+			expectAuthorized: false,
+		},
 	}
 
 	for _, tt := range tests {
@@ -151,3 +199,33 @@ func TestFilerServer_maybeCheckJwtAuthorization_Scoped(t *testing.T) {
 		})
 	}
 }
+
+func TestPathHasComponentPrefix(t *testing.T) {
+	tests := []struct {
+		name   string
+		path   string
+		prefix string
+		want   bool
+	}{
+		{"exact match", "/tenant1", "/tenant1", true},
+		{"subtree match", "/tenant1/a/b", "/tenant1", true},
+		{"trailing slash prefix", "/tenant1/a", "/tenant1/", true},
+		{"sibling numeric suffix", "/tenant1234/secret", "/tenant1", false},
+		{"sibling dash suffix", "/tenant1-old/secret", "/tenant1", false},
+		{"sibling dot suffix", "/tenant1.bak/x", "/tenant1", false},
+		{"unrelated tree", "/other/x", "/tenant1", false},
+		{"root prefix matches root", "/", "/", true},
+		{"root prefix matches any", "/tenant1234/secret", "/", true},
+		{"empty prefix denies", "/tenant1/x", "", false},
+		{"dot-dot does not escape", "/tenant1/../tenant2/secret", "/tenant1", false},
+		{"dot-dot stays inside", "/tenant1/a/../b", "/tenant1", true},
+		{"double slashes normalised", "/tenant1//a", "/tenant1", true},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := pathHasComponentPrefix(tt.path, tt.prefix); got != tt.want {
+				t.Errorf("pathHasComponentPrefix(%q, %q) = %v, want %v", tt.path, tt.prefix, got, tt.want)
+			}
+		})
+	}
+}
diff --git a/weed/server/filer_server_handlers.go b/weed/server/filer_server_handlers.go
index 8c27244f6..d61e529ac 100644
--- a/weed/server/filer_server_handlers.go
+++ b/weed/server/filer_server_handlers.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"net/http"
+	"path"
 	"strconv"
 	"strings"
 	"sync/atomic"
@@ -256,7 +257,7 @@ func (fs *FilerServer) maybeCheckJwtAuthorization(r *http.Request, isWrite bool)
 	if len(claims.AllowedPrefixes) > 0 {
 		hasPrefix := false
 		for _, prefix := range claims.AllowedPrefixes {
-			if strings.HasPrefix(r.URL.Path, prefix) {
+			if pathHasComponentPrefix(r.URL.Path, prefix) {
 				hasPrefix = true
 				break
 			}
@@ -283,6 +284,32 @@ func (fs *FilerServer) maybeCheckJwtAuthorization(r *http.Request, isWrite bool)
 	return true
 }
 
+// pathHasComponentPrefix reports whether reqPath is contained within the
+// directory subtree denoted by prefix, treating both as "/"-separated
+// path components. Both inputs are normalised with path.Clean to neutralise
+// "." and ".." segments and collapse duplicate slashes. A prefix of "/"
+// matches any path.
+func pathHasComponentPrefix(reqPath, prefix string) bool {
+	if prefix == "" {
+		return false
+	}
+	cleanedPath := path.Clean(reqPath)
+	if cleanedPath == "." {
+		cleanedPath = "/"
+	}
+	cleanedPrefix := path.Clean(prefix)
+	if cleanedPrefix == "." {
+		cleanedPrefix = "/"
+	}
+	if cleanedPrefix == "/" {
+		return true
+	}
+	if cleanedPath == cleanedPrefix {
+		return true
+	}
+	return strings.HasPrefix(cleanedPath, cleanedPrefix+"/")
+}
+
 func (fs *FilerServer) filerHealthzHandler(w http.ResponseWriter, r *http.Request) {
 	w.Header().Set("Server", "SeaweedFS "+version.VERSION)
 	if _, err := fs.filer.Store.FindEntry(context.Background(), filer.TopicsDir); err != nil && err != filer_pb.ErrNotFound {