diff --git a/ChangeLog b/ChangeLog
index 44e1d9990..29da03d0e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -49,6 +49,8 @@
 - TW-1302 CmdShow.cpp:244: bad length in substr ? (thanks to David Binderman).
 - TW-1304 Minor build and install fix for NetBSD (thanks to atomicules).
 - TW-1307 burndown is aliased to burndown.weekly (thanks to darkfeline).
+- TW-1309 memory error, if misconfigured calendar.details.report (thanks to
+          Onion).
 - Removed deprecated 'echo.command' setting, in favor of the 'header' and
   'affected' verbosity tokens.
 - Removed deprecated 'edit.verbose' setting, in favor of the 'edit' verbosity
diff --git a/src/commands/CmdCalendar.cpp b/src/commands/CmdCalendar.cpp
index 484710b73..189bfe0ee 100644
--- a/src/commands/CmdCalendar.cpp
+++ b/src/commands/CmdCalendar.cpp
@@ -331,7 +331,11 @@ int CmdCalendar::execute (std::string& output)
     // Table with due date information
     if (context.config.get ("calendar.details") == "full")
     {
+      // Assert that 'report' is a valid report.
       std::string report = context.config.get ("calendar.details.report");
+      if (context.commands.find (report) == context.commands.end ())
+        throw std::string (STRING_ERROR_DETAILS);
+
       std::string report_filter = context.config.get ("report." + report + ".filter");
 
       context.a3.clear ();
diff --git a/src/eng-USA.h b/src/eng-USA.h
index 7d4f9f20d..77c8ae878 100644
--- a/src/eng-USA.h
+++ b/src/eng-USA.h
@@ -691,6 +691,7 @@
 #define STRING_INVALID_SORT_COL      "The '{1}' column is not a valid sort field."
 #define STRING_TLS_INIT_FAIL         "Error initializing TLS."
 #define STRING_ERROR_MEMORY          "Problem obtaining memory."
+#define STRING_ERROR_DETAILS         "The setting 'calendar.details.report' must contain a single report name."
 
 // Feedback
 #define STRING_FEEDBACK_NO_TASKS     "No tasks."
diff --git a/src/esp-ESP.h b/src/esp-ESP.h
index 0ed69b758..5b50ef81a 100644
--- a/src/esp-ESP.h
+++ b/src/esp-ESP.h
@@ -704,6 +704,7 @@
 #define STRING_INVALID_SORT_COL      "La columna '{1}' no es un campo de ordenación válido."
 #define STRING_TLS_INIT_FAIL         "Error inicializando TLS."
 #define STRING_ERROR_MEMORY          "Problem obtaining memory."
+#define STRING_ERROR_DETAILS         "The setting 'calendar.details.report' must contain a single report name."
 
 // Feedback
 #define STRING_FEEDBACK_NO_TASKS     "Ninguna tarea."
diff --git a/src/fra-FRA.h b/src/fra-FRA.h
index 52506c0d1..ccc2a62fe 100644
--- a/src/fra-FRA.h
+++ b/src/fra-FRA.h
@@ -690,6 +690,7 @@
 #define STRING_INVALID_SORT_COL      "The '{1}' column is not a valid sort field."
 #define STRING_TLS_INIT_FAIL         "Error initializing TLS."
 #define STRING_ERROR_MEMORY          "Problem obtaining memory."
+#define STRING_ERROR_DETAILS         "The setting 'calendar.details.report' must contain a single report name."
 
 // Feedback
 #define STRING_FEEDBACK_NO_TASKS     "No tasks."
diff --git a/src/ita-ITA.h b/src/ita-ITA.h
index 3cd506732..f41bb8e2a 100644
--- a/src/ita-ITA.h
+++ b/src/ita-ITA.h
@@ -691,6 +691,7 @@
 #define STRING_INVALID_SORT_COL      "La colonna '{1}' non è un campo di ordinamento valido."
 #define STRING_TLS_INIT_FAIL         "Error initializing TLS."
 #define STRING_ERROR_MEMORY          "Problem obtaining memory."
+#define STRING_ERROR_DETAILS         "The setting 'calendar.details.report' must contain a single report name."
 
 // Feedback
 #define STRING_FEEDBACK_NO_TASKS     "Nessun task."
diff --git a/src/por-PRT.h b/src/por-PRT.h
index 6fc541ccb..af282d374 100644
--- a/src/por-PRT.h
+++ b/src/por-PRT.h
@@ -691,6 +691,7 @@
 #define STRING_INVALID_SORT_COL      "A coluna '{1}' não pode ser ordenada."
 #define STRING_TLS_INIT_FAIL         "Erro a iniciar componente TLS."
 #define STRING_ERROR_MEMORY          "Problem obtaining memory."
+#define STRING_ERROR_DETAILS         "The setting 'calendar.details.report' must contain a single report name."
 
 // Feedback
 #define STRING_FEEDBACK_NO_TASKS     "Nenhuma tarefa."