core: fix possible buffer overflow in command /color alias (issue #2330)

Fix: c.lang.security.insecure-use-strcat-fn.insecure-use-strcat-fn security vulnerability

Automated security fix generated by OrbisAI Security

CHANGELOG.md

@@ -8,6 +8,7 @@
 
 ### Fixed
 
+- core: fix possible buffer overflow in command /color alias ([#2330](https://github.com/weechat/weechat/issues/2330))
 - core: fix buffer overflow in connection to SOCKS5 proxy ([#2325](https://github.com/weechat/weechat/issues/2325))
 - api: fix infinite loop in function string_replace when the search string is empty
 - irc: limit size of data received from the server to prevent memory exhaustion

src/core/core-command.c

@@ -1711,17 +1711,12 @@ COMMAND_CALLBACK(color)
             else
                 str_alias = argv[i];
         }
-        str_color[0] = '\0';
-        if (str_alias)
-        {
-            strcat (str_color, ";");
-            strcat (str_color, str_alias);
-        }
-        if (str_rgb)
-        {
-            strcat (str_color, ";");
-            strcat (str_color, str_rgb);
-        }
+        snprintf (str_color, sizeof (str_color),
+                  "%s%s%s%s",
+                  (str_alias) ? ";" : "",
+                  (str_alias) ? str_alias : "",
+                  (str_rgb) ? ";" : "",
+                  (str_rgb) ? str_rgb : "");
 
         /* add color alias */
         snprintf (str_command, sizeof (str_command),