diff --git a/solver/llbsolver/file/backend.go b/solver/llbsolver/file/backend.go
index 3e380d53b..be431a4f7 100644
--- a/solver/llbsolver/file/backend.go
+++ b/solver/llbsolver/file/backend.go
@@ -162,12 +162,12 @@ func rm(d string, action *pb.FileActionRm) (err error) {
 }
 
 func rmPath(root, src string, allowNotFound bool) error {
-	src = filepath.Clean(src)
+	src = filepath.Join("/", src)
 	dir, base := filepath.Split(src)
 	if base == "" {
 		return errors.New("rmPath: invalid empty path")
 	}
-	dir, err := fs.RootPath(root, filepath.Join("/", dir))
+	dir, err := fs.RootPath(root, dir)
 	if err != nil {
 		return errors.WithStack(err)
 	}
diff --git a/solver/llbsolver/file/backend_test.go b/solver/llbsolver/file/backend_test.go
index 41bda56d9..3c9d798ed 100644
--- a/solver/llbsolver/file/backend_test.go
+++ b/solver/llbsolver/file/backend_test.go
@@ -5,6 +5,7 @@ import (
 	"path/filepath"
 	"testing"
 
+	"github.com/moby/buildkit/solver/pb"
 	"github.com/pkg/errors"
 	"github.com/stretchr/testify/require"
 )
@@ -35,3 +36,45 @@ func TestRmPathFileExists(t *testing.T) {
 
 	require.True(t, os.IsNotExist(err))
 }
+
+func TestRmParentTraversalDoesNotEscapeRoot(t *testing.T) {
+	// Backslash variants are separators on Windows (real traversal there) and
+	// ordinary filename characters on Linux (inert, but still must not escape).
+	for _, p := range []string{
+		"..", "../..", "a/../..", "../victim",
+		"..\\..", "a\\..\\..", "..\\victim",
+	} {
+		t.Run(p, func(t *testing.T) {
+			parent := t.TempDir()
+			root := filepath.Join(parent, "root")
+			victim := filepath.Join(parent, "victim")
+
+			require.NoError(t, os.Mkdir(root, 0o755))
+			require.NoError(t, os.Mkdir(victim, 0o755))
+			require.NoError(t, os.WriteFile(filepath.Join(victim, "data"), []byte("data"), 0o644))
+
+			require.Error(t, rm(root, &pb.FileActionRm{Path: p}))
+
+			_, err := os.Stat(victim)
+			require.NoError(t, err, "rm escaped root and deleted sibling %q", victim)
+		})
+	}
+}
+
+func TestRmPathRemovesSymlinkItself(t *testing.T) {
+	root := t.TempDir()
+
+	target := filepath.Join(root, "target")
+	link := filepath.Join(root, "link")
+
+	require.NoError(t, os.WriteFile(target, []byte("target"), 0o644))
+	require.NoError(t, os.Symlink("target", link))
+
+	require.NoError(t, rmPath(root, "link", false))
+
+	_, err := os.Lstat(link)
+	require.True(t, os.IsNotExist(err))
+
+	_, err = os.Stat(target)
+	require.NoError(t, err)
+}