diff --git a/fuzz/Makefile b/fuzz/Makefile
index d1cbba332466f94b190317b63527e2ea8a9bc47a..e7ed256f30e3bc87e3fbd90421b7d922948e99cc 100644
--- a/fuzz/Makefile
+++ b/fuzz/Makefile
@@ -1,6 +1,7 @@
-SWITCH := 4.11.1+afl
-EXE := src/Main.exe
+# The switch that is used for testing is named in the file default.switch.
+SWITCH := $(shell cat default.switch)
 
+EXE := src/Main.exe
 
 # This line is somewhat problematic, as it assumes that ocamlfind and
 # monolith are installed in the current switch, whatever it is.
diff --git a/fuzz/default.switch b/fuzz/default.switch
new file mode 100644
index 0000000000000000000000000000000000000000..20bb284555bcd9d49d8196ed404b947c2188d609
--- /dev/null
+++ b/fuzz/default.switch
@@ -0,0 +1 @@
+4.11.1+afl