diff --git a/assets/release/Dockerfiles/Dockerfile.amd64.ubuntu-18.04 b/assets/release/Dockerfiles/Dockerfile.amd64.ubuntu-18.04
index 37b180d72..4fcbeba49 100644
--- a/assets/release/Dockerfiles/Dockerfile.amd64.ubuntu-18.04
+++ b/assets/release/Dockerfiles/Dockerfile.amd64.ubuntu-18.04
@@ -16,6 +16,15 @@ RUN apt-get update && \
         clang \
         curl
 
+# Install CMake >= 3.12 (required by wabt-sys,
+# which is required by cwabt, used by the V8 backend).
+RUN apt-get install -y --no-install-recommends \
+        python3-pip \
+        python3-setuptools && \
+        pip3 install --upgrade pip && \
+        pip3 install scikit-build && \
+        pip3 install cmake
+
 ENV RUSTUP_HOME=/usr/local/rustup CARGO_HOME=/usr/local/cargo
 ENV PATH $CARGO_HOME/bin:$PATH
 RUN mkdir -p "$CARGO_HOME" && mkdir -p "$RUSTUP_HOME" && \
diff --git a/util/runtimes/v8.sh b/util/runtimes/v8.sh
index 3d250000c..0ec230cd3 100755
--- a/util/runtimes/v8.sh
+++ b/util/runtimes/v8.sh
@@ -17,7 +17,7 @@ source $NGX_WASM_DIR/util/_lib.sh
 
 build_cwabt() {
     local target="$1"
-    local clean="$1"
+    local clean="$2"
 
     notice "building lib/cwabt..."