diff --git a/kernel.spec b/kernel.spec
index 9a125d2..0c4c3fe 100644
--- a/kernel.spec
+++ b/kernel.spec
@@ -53,6 +53,8 @@ BuildRequires:  bc
 BuildRequires:  openssl-devel
 BuildRequires:  gcc-plugin-devel
 BuildRequires:  elfutils-libelf-devel
+BuildRequires:  bison
+BuildRequires:  flex
 
 # gcc with support for BTI mitigation
 %if 0%{?fedora} == 23