diff --git a/CASA-auth-token/client/library/engine.c b/CASA-auth-token/client/library/engine.c
index 64900550..36e08ef8 100644
--- a/CASA-auth-token/client/library/engine.c
+++ b/CASA-auth-token/client/library/engine.c
@@ -1054,6 +1054,11 @@ SetATSHostList(
 
    for (i = 0; ATSHostList[i] != NULL; i++) {
       int ret;
+      if (strlen(ATSHostList[i]) > 255) {
+         DbgTrace(0, "-SetATSHostList- Host name too long: %s\n", ATSHostList[i]);
+         retStatus = CASA_STATUS_INVALID_PARAMETER;
+         goto exit;
+      }
       ret = sscanf(ATSHostList[i], "%[^:]:%hu", address, &port);
       if (ret != 2) {
          DbgTrace(0, "-SetATSHostList- Invalid entry: %s\n", ATSHostList[i]);