diff --git a/ChangeLog.adoc b/ChangeLog.adoc
index db74d5bad..e91bd2ab2 100644
--- a/ChangeLog.adoc
+++ b/ChangeLog.adoc
@@ -15,6 +15,13 @@ https://weechat.org/files/releasenotes/ReleaseNotes-devel.html[release notes]
 (file _ReleaseNotes.adoc_ in sources).
 
 
+[[v3.0.1]]
+== Version 3.0.1 (under dev)
+
+Bug fixes::
+
+  * spell: fix crash with IRC color codes in command line (issue #1589)
+
 [[v3.0]]
 == Version 3.0 (2020-11-11)
 
diff --git a/src/plugins/spell/spell.c b/src/plugins/spell/spell.c
index 62a88388c..4ecd3a433 100644
--- a/src/plugins/spell/spell.c
+++ b/src/plugins/spell/spell.c
@@ -649,7 +649,7 @@ spell_skip_color_codes (char **string, char **result)
 {
     int color_code_size;
 
-    while (*string[0])
+    while ((*string)[0])
     {
         color_code_size = weechat_string_color_code_size (*string);
         if (color_code_size > 0)
@@ -658,9 +658,9 @@ spell_skip_color_codes (char **string, char **result)
             weechat_string_dyn_concat (result, *string, color_code_size);
             (*string) += color_code_size;
         }
-        else if (*string[0] == '\x02' || *string[0] == '\x0F'
-                 || *string[0] == '\x11' || *string[0] == '\x16'
-                 || *string[0] == '\x1D' || *string[0] == '\x1F')
+        else if ((*string)[0] == '\x02' || (*string)[0] == '\x0F'
+                 || (*string)[0] == '\x11' || (*string)[0] == '\x16'
+                 || (*string)[0] == '\x1D' || (*string)[0] == '\x1F')
         {
             /*
              * IRC attribute:
@@ -674,28 +674,29 @@ spell_skip_color_codes (char **string, char **result)
             weechat_string_dyn_concat (result, *string, 1);
             (*string)++;
         }
-        else if (*string[0] == '\x03')
+        else if ((*string)[0] == '\x03')
         {
             /* IRC color code */
             weechat_string_dyn_concat (result, *string, 1);
             (*string)++;
-            if (isdigit (*string[0]))
+            if (isdigit ((unsigned char)((*string)[0])))
             {
                 /* foreground */
                 weechat_string_dyn_concat (result, *string, 1);
                 (*string)++;
-                if (isdigit (*string[0]))
+                if (isdigit ((unsigned char)((*string)[0])))
                 {
                     weechat_string_dyn_concat (result, *string, 1);
                     (*string)++;
                 }
             }
-            if ((*string[0] == ',') && (isdigit (*string[1])))
+            if (((*string)[0] == ',')
+                && (isdigit ((unsigned char)((*string)[1]))))
             {
                 /* background */
                 weechat_string_dyn_concat (result, *string, 1);
                 (*string)++;
-                if (isdigit (*string[0]))
+                if (isdigit ((unsigned char)((*string)[0])))
                 {
                     weechat_string_dyn_concat (result, *string, 1);
                     (*string)++;