diff --git a/changelogs/fragments/777-interfaces_file-re-escape.yml b/changelogs/fragments/777-interfaces_file-re-escape.yml
new file mode 100644
index 0000000000..a7daee5670
--- /dev/null
+++ b/changelogs/fragments/777-interfaces_file-re-escape.yml
@@ -0,0 +1,3 @@
+---
+bugfixes:
+- interfaces_file - escape regular expression characters in old value (https://github.com/ansible-collections/community.general/issues/777).
diff --git a/plugins/modules/system/interfaces_file.py b/plugins/modules/system/interfaces_file.py
index 7684bf485e..6f5c3a618c 100644
--- a/plugins/modules/system/interfaces_file.py
+++ b/plugins/modules/system/interfaces_file.py
@@ -284,7 +284,7 @@ def setInterfaceOption(module, lines, iface, option, raw_value, state, address_f
                     address_family = target_option['address_family']
                     prefix_start = old_line.find(option)
                     optionLen = len(option)
-                    old_value_position = re.search(r"\s+".join(old_value.split()), old_line[prefix_start + optionLen:])
+                    old_value_position = re.search(r"\s+".join(map(re.escape, old_value.split())), old_line[prefix_start + optionLen:])
                     start = old_value_position.start() + prefix_start + optionLen
                     end = old_value_position.end() + prefix_start + optionLen
                     line = old_line[:start] + value + old_line[end:]