diff --git a/python3.12-flit-core.spec b/python3.12-flit-core.spec
index ab85d1c..35e8b51 100644
--- a/python3.12-flit-core.spec
+++ b/python3.12-flit-core.spec
@@ -1,6 +1,11 @@
 %global __python3 /usr/bin/python3.12
 %global python3_pkgversion 3.12
 
+# Workaround for https://issues.redhat.com/browse/CS-1907
+# By defining the %%{__bootstrap} value,
+# we prevent misconfigured Koji putting a literal %%{__bootstrap} in %%dist.
+%{!?__bootstrap:%global __bootstrap %{nil}}
+
 # When bootstrapping new Python we need to build flit in bootstrap mode.
 # The Python RPM dependency generators and pip are not yet available.
 %bcond_without bootstrap