diff --git a/src/calng/CrystfelRunner.py b/src/calng/CrystfelRunner.py
index 0406429370a5e0a93fda65a8c775470b8abde7a3..15baa40566caf1cddcff9957ea098d06022f95a3 100644
--- a/src/calng/CrystfelRunner.py
+++ b/src/calng/CrystfelRunner.py
@@ -350,13 +350,15 @@ class CrystfelRunner(PythonDevice):
         self.KARABO_ON_INPUT("input", self.input_handler)
 
         # note: loading with cfelpyutils.geometry does not tell us peak_list value
+        # extra note: we need to avoid taking ';' and ' ' into the path!
+        # (Hence the large regexp on the right-hand side)
         self._geom_data_path = None
         self._geom_peak_path = None
         with open(self.get("crystfelArgs.geometryPath"), "rt") as fd:
             for line in fd:
-                if (match := re.match(r"data\s*=\s*(.*)$", line)):
+                if (match := re.match(r"data\s*=\s*([a-zA-Z0-9/\._]*)", line)):
                     self._geom_data_path = match.group(1)
-                elif (match := re.match(r"peak_list\s*=\s*(.*)$", line)):
+                elif (match := re.match(r"peak_list\s*=\s*([a-zA-Z0-9/\._]*)", line)):
                     self._geom_peak_path = match.group(1)
                 if None not in (self._geom_data_path, self._geom_peak_path):
                     break