diff --git a/dockerfiles/contracts-ci-linux/Dockerfile b/dockerfiles/contracts-ci-linux/Dockerfile
index 16613213..9ae7aba0 100644
--- a/dockerfiles/contracts-ci-linux/Dockerfile
+++ b/dockerfiles/contracts-ci-linux/Dockerfile
@@ -22,6 +22,10 @@ dockerfiles/contracts-ci-linux/README.md" \
 COPY utility/debian-llvm-clang.key /etc/apt/trusted.gpg.d/debian-archive-llvm.gpg
 COPY utility/yarn.key /etc/apt/trusted.gpg.d/debian-yarn.gpg
 
+# Necessary for building binaryen-sys, which is part of cargo-contract's
+# binaryen dependency
+ENV CXX="/usr/bin/clang++-8"
+
 # install tools and dependencies
 RUN set -eux; \
 	echo "deb https://dl.yarnpkg.com/debian/ stable main"  \
diff --git a/dockerfiles/ink-ci-linux/Dockerfile b/dockerfiles/ink-ci-linux/Dockerfile
index 5db66e37..bdd08afb 100644
--- a/dockerfiles/ink-ci-linux/Dockerfile
+++ b/dockerfiles/ink-ci-linux/Dockerfile
@@ -17,6 +17,10 @@ dockerfiles/ink-ci-linux/README.md" \
 	io.parity.image.revision="${VCS_REF}" \
 	io.parity.image.created="${BUILD_DATE}"
 
+# Necessary for building binaryen-sys, which is part of cargo-contract's
+# binaryen dependency
+ENV CXX="/usr/bin/clang++-8"
+
 RUN	set -eux; \
 # The supported Rust nightly version must support the following components
 # to allow for a functioning CI pipeline: