diff --git a/fluent-package/templates/package-scripts/fluent-package/deb/postinst b/fluent-package/templates/package-scripts/fluent-package/deb/postinst
index 62b19dfe..e2c93cce 100755
--- a/fluent-package/templates/package-scripts/fluent-package/deb/postinst
+++ b/fluent-package/templates/package-scripts/fluent-package/deb/postinst
@@ -164,6 +164,10 @@ install_missing_plugins() {
 		cat $local_missing_gems
 		while read gem
 		do
+		    if [ "$gem" = "readline-ext" ]; then
+			# readline-ext is unbundled since ruby 3.3
+			continue
+		    fi
 		    if ! /usr/sbin/fluent-gem install --no-document $gem; then
 			echo "Can't install missing gem automatically: please install $gem manually."
 		    fi
diff --git a/fluent-package/yum/fluent-package.spec.in b/fluent-package/yum/fluent-package.spec.in
index 4e8836d2..12dc04d9 100644
--- a/fluent-package/yum/fluent-package.spec.in
+++ b/fluent-package/yum/fluent-package.spec.in
@@ -322,6 +322,10 @@ if [ $1 -eq 2 ]; then
 	echo "Install missing dependency gems..."
 	while read gem
 	do
+	  if [ "$gem" = "readline-ext" ]; then
+	    # readline-ext is unbundled since ruby 3.3
+	    continue
+	  fi
           if ! /usr/sbin/fluent-gem install --no-document $gem; then
 	    echo "Can't install missing gem automatically, please install $gem manually."
           fi