diff --git a/debian/gitlab-ci.yml b/debian/gitlab-ci.yml
index aff830284f069dc3250f7013fba6eb60e98c7f97..e59c777ed447603202fbfbad324551a2ab3a9364 100644
--- a/debian/gitlab-ci.yml
+++ b/debian/gitlab-ci.yml
@@ -50,6 +50,7 @@ ubsan:
                 ${NULL+}
 
             export CC=clang
+            export CXX=clang++
 
             rm -fr builddir
             meson \