diff --git a/internal/gitaly/service/operations/commit_files.go b/internal/gitaly/service/operations/commit_files.go
index 5913288f05d20bab5012df8a3f03061424c95537..373af1749f25117eeccec1322c8b193fbc5e3cb6 100644
--- a/internal/gitaly/service/operations/commit_files.go
+++ b/internal/gitaly/service/operations/commit_files.go
@@ -256,6 +256,18 @@ func applyAction(
 			return translateError(err, action.Path)
 		}
 	case updateFile:
+		entry, err := root.Get(action.Path)
+		if err != nil {
+			return translateError(err, action.Path)
+		}
+
+		if entry.Type != localrepo.Blob {
+			return indexError{
+				path:      action.Path,
+				errorType: errFileNotFound,
+			}
+		}
+
 		if err := root.Modify(
 			action.Path,
 			func(entry *localrepo.TreeEntry) error {
@@ -415,7 +427,6 @@ func (s *Server) userCommitFilesGit(
 	header *gitalypb.UserCommitFilesRequestHeader,
 	parentCommitOID git.ObjectID,
 	quarantineRepo *localrepo.Repo,
-	repoPath string,
 	actions []commitAction,
 ) (git.ObjectID, error) {
 	committerSignature, err := git.SignatureFromRequest(header)
@@ -693,7 +704,6 @@ func (s *Server) userCommitFiles(
 		header,
 		parentCommitOID,
 		quarantineRepo,
-		repoPath,
 		actions,
 	)
 	if err != nil {
diff --git a/internal/gitaly/service/operations/commit_files_test.go b/internal/gitaly/service/operations/commit_files_test.go
index e4f7dcf568980273979b05ec8495ba70db877c91..eb305121db152d60e5b4ec2972e43363eb11ef8f 100644
--- a/internal/gitaly/service/operations/commit_files_test.go
+++ b/internal/gitaly/service/operations/commit_files_test.go
@@ -459,6 +459,28 @@ func testUserCommitFiles(t *testing.T, ctx context.Context) {
 				},
 			},
 		},
+		{
+			desc: "update file fails if the target is a directory",
+			steps: []step{
+				{
+					actions: []*gitalypb.UserCommitFilesRequest{
+						createDirHeaderRequest("directory"),
+					},
+					repoCreated:   true,
+					branchCreated: true,
+					treeEntries: []gittest.TreeEntry{
+						{Mode: DefaultMode, Path: "directory/.gitkeep"},
+					},
+				},
+				{
+					actions: []*gitalypb.UserCommitFilesRequest{
+						updateFileHeaderRequest("directory"),
+						actionContentRequest("content"),
+					},
+					expectedErr: structuredIndexError(t, &indexError{path: "directory", errorType: errFileNotFound}),
+				},
+			},
+		},
 		{
 			desc: "move file with traversal in source",
 			steps: []step{