diff --git a/src/keymap_manager.cc b/src/keymap_manager.cc
index 81efe7ed..26579bf7 100644
--- a/src/keymap_manager.cc
+++ b/src/keymap_manager.cc
@@ -13,6 +13,9 @@ namespace Kakoune
 void KeymapManager::map_key(Key key, KeymapMode mode,
                             KeyList mapping, String docstring)
 {
+    if (auto it = m_mapping.find(KeyAndMode{key, mode}); it != m_mapping.end())
+        if (it->value.is_executing)
+            throw runtime_error("cannot map key that is currently executing");
     m_mapping[KeyAndMode{key, mode}] = {std::move(mapping), std::move(docstring)};
 }
 
diff --git a/test/regression/4896-remap-executing-mapping/cmd b/test/regression/4896-remap-executing-mapping/cmd
new file mode 100644
index 00000000..a09e364c
--- /dev/null
+++ b/test/regression/4896-remap-executing-mapping/cmd
@@ -0,0 +1,3 @@
+!printf $kak_opt_source_count<ret>l
+<space>s
+!printf $kak_opt_source_count<ret>
diff --git a/test/regression/4896-remap-executing-mapping/in b/test/regression/4896-remap-executing-mapping/in
new file mode 100644
index 00000000..8b137891
--- /dev/null
+++ b/test/regression/4896-remap-executing-mapping/in
@@ -0,0 +1 @@
+
diff --git a/test/regression/4896-remap-executing-mapping/out b/test/regression/4896-remap-executing-mapping/out
new file mode 100644
index 00000000..48082f72
--- /dev/null
+++ b/test/regression/4896-remap-executing-mapping/out
@@ -0,0 +1 @@
+12
diff --git a/test/regression/4896-remap-executing-mapping/rc b/test/regression/4896-remap-executing-mapping/rc
new file mode 100644
index 00000000..56624d18
--- /dev/null
+++ b/test/regression/4896-remap-executing-mapping/rc
@@ -0,0 +1,3 @@
+try %{ map global user s %exp{:source %%{%val{source}}<ret>} -docstring "re-source my kakrc" }
+declare-option int source_count
+set-option -add global source_count 1