diff --git a/pkg/storage/fs/owncloud/owncloud.go b/pkg/storage/fs/owncloud/owncloud.go
index bad1b6d53c9..76be9061aaf 100644
--- a/pkg/storage/fs/owncloud/owncloud.go
+++ b/pkg/storage/fs/owncloud/owncloud.go
@@ -263,7 +263,9 @@ func (fs *ocfs) toInternalPath(ctx context.Context, sp string) (ip string) {
 	if fs.c.EnableHome {
 		u := user.ContextMustGetUser(ctx)
 		layout := templates.WithUser(u, fs.c.UserLayout)
-		ip = filepath.Join(fs.c.DataDirectory, layout, "files", sp)
+		// The inner filepath.Join prevents the path from breaking out of
+		// <fs.c.DataDirectory>/<layout>/files/
+		ip = filepath.Join(fs.c.DataDirectory, layout, "files", filepath.Join("/", sp))
 	} else {
 		// trim all /
 		sp = strings.Trim(sp, "/")
@@ -290,7 +292,7 @@ func (fs *ocfs) toInternalPath(ctx context.Context, sp string) (ip string) {
 			ip = filepath.Join(fs.c.DataDirectory, layout, "files")
 		} else {
 			// parts = "<username>", "foo/bar.txt"
-			ip = filepath.Join(fs.c.DataDirectory, layout, "files", segments[1])
+			ip = filepath.Join(fs.c.DataDirectory, layout, "files", filepath.Join(segments[1]))
 		}
 
 	}
@@ -362,7 +364,7 @@ func (fs *ocfs) getVersionsPath(ctx context.Context, ip string) string {
 		return filepath.Join(fs.c.DataDirectory, layout, "files_versions")
 	case 4:
 		// parts = "", "<username>", "foo/bar.txt"
-		return filepath.Join(fs.c.DataDirectory, layout, "files_versions", parts[3])
+		return filepath.Join(fs.c.DataDirectory, layout, "files_versions", filepath.Join("/", parts[3]))
 	default:
 		return "" // TODO Must not happen?
 	}
@@ -799,7 +801,7 @@ func (fs *ocfs) resolve(ctx context.Context, ref *provider.Reference) (string, e
 		if err != nil {
 			return "", err
 		}
-		filepath.Join("/", ip, ref.Path)
+		filepath.Join("/", ip, filepath.Join("/", ref.Path))
 		return ip, nil
 	}
 
diff --git a/pkg/storage/fs/owncloud/upload.go b/pkg/storage/fs/owncloud/upload.go
index e48f1c74943..181f86e643f 100644
--- a/pkg/storage/fs/owncloud/upload.go
+++ b/pkg/storage/fs/owncloud/upload.go
@@ -263,7 +263,7 @@ func (fs *ocfs) getUploadPath(ctx context.Context, uploadID string) (string, err
 
 // GetUpload returns the Upload for the given upload id
 func (fs *ocfs) GetUpload(ctx context.Context, id string) (tusd.Upload, error) {
-	infoPath := filepath.Join(fs.c.UploadInfoDir, id+".info")
+	infoPath := filepath.Join(fs.c.UploadInfoDir, filepath.Join("/", id+".info"))
 
 	info := tusd.FileInfo{}
 	data, err := ioutil.ReadFile(infoPath)
diff --git a/pkg/storage/utils/chunking/chunking.go b/pkg/storage/utils/chunking/chunking.go
index 5130d88772b..656ec14fe91 100644
--- a/pkg/storage/utils/chunking/chunking.go
+++ b/pkg/storage/utils/chunking/chunking.go
@@ -96,7 +96,7 @@ func (c *ChunkHandler) createChunkTempFile() (string, *os.File, error) {
 }
 
 func (c *ChunkHandler) getChunkFolderName(i *ChunkBLOBInfo) (string, error) {
-	path := "/" + c.ChunkFolder + filepath.Clean("/"+i.uploadID())
+	path := filepath.Join("/", c.ChunkFolder, filepath.Join("/", i.uploadID()))
 	if err := os.MkdirAll(path, 0755); err != nil {
 		return "", err
 	}
@@ -132,7 +132,7 @@ func (c *ChunkHandler) saveChunk(path string, r io.ReadCloser) (bool, string, er
 	}
 	// c.logger.Info().Log("chunkfolder", chunksFolderName)
 
-	chunkTarget := chunksFolderName + "/" + fmt.Sprintf("%d", chunkInfo.CurrentChunk)
+	chunkTarget := filepath.Join(chunksFolderName, strconv.Itoa(chunkInfo.CurrentChunk))
 	if err = os.Rename(chunkTempFilename, chunkTarget); err != nil {
 		return false, "", err
 	}
@@ -171,7 +171,7 @@ func (c *ChunkHandler) saveChunk(path string, r io.ReadCloser) (bool, string, er
 
 	// walk all chunks and append to assembled file
 	for i := range chunks {
-		target := chunksFolderName + "/" + fmt.Sprintf("%d", i)
+		target := filepath.Join(chunksFolderName, strconv.Itoa(i))
 
 		chunk, err := os.Open(target)
 		if err != nil {
diff --git a/pkg/storage/utils/decomposedfs/node/node.go b/pkg/storage/utils/decomposedfs/node/node.go
index 55af74eb5c4..660165ef322 100644
--- a/pkg/storage/utils/decomposedfs/node/node.go
+++ b/pkg/storage/utils/decomposedfs/node/node.go
@@ -200,7 +200,7 @@ func isNotDir(err error) bool {
 
 // Child returns the child node with the given name
 func (n *Node) Child(ctx context.Context, name string) (*Node, error) {
-	link, err := os.Readlink(filepath.Join(n.InternalPath(), name))
+	link, err := os.Readlink(filepath.Join(n.InternalPath(), filepath.Join("/", name)))
 	if err != nil {
 		if os.IsNotExist(err) || isNotDir(err) {
 			c := &Node{
diff --git a/pkg/storage/utils/localfs/localfs.go b/pkg/storage/utils/localfs/localfs.go
index c8d5cc2fbc2..e0c6464fe14 100644
--- a/pkg/storage/utils/localfs/localfs.go
+++ b/pkg/storage/utils/localfs/localfs.go
@@ -161,6 +161,9 @@ func getUser(ctx context.Context) (*userpb.User, error) {
 }
 
 func (fs *localfs) wrap(ctx context.Context, p string) string {
+	// This is to prevent path traversal.
+	// With this p can't break out of its parent folder
+	p = path.Join("/", p)
 	var internal string
 	if !fs.conf.DisableHome {
 		layout, err := fs.GetHome(ctx)
@@ -203,6 +206,7 @@ func (fs *localfs) wrapRecycleBin(ctx context.Context, p string) string {
 }
 
 func (fs *localfs) wrapVersions(ctx context.Context, p string) string {
+	p = path.Join("/", p)
 	var internal string
 	if !fs.conf.DisableHome {
 		layout, err := fs.GetHome(ctx)