diff --git a/UPGRADING b/UPGRADING
index b7b160820bb2a..e55b9730f71a4 100644
--- a/UPGRADING
+++ b/UPGRADING
@@ -246,6 +246,7 @@ PHP 8.6 UPGRADE NOTES
     creation of intermediate Closures, the overhead of calling userland
     callbacks from internal functions and providing for better insight for the
     JIT.
+  . The performance of the TAILCALL VM has been improved.
 
 - DOM:
   . Made splitText() faster and consume less memory.
diff --git a/Zend/zend_vm_execute.h b/Zend/zend_vm_execute.h
index cbfae90802cfa..7dfedca98d3b9 100644
--- a/Zend/zend_vm_execute.h
+++ b/Zend/zend_vm_execute.h
@@ -53457,6 +53457,8 @@ static ZEND_OPCODE_HANDLER_RET ZEND_OPCODE_HANDLER_FUNC_CCONV ZEND_NULL_HANDLER(
 # undef ZEND_VM_RETURN
 # undef ZEND_VM_DISPATCH_TO_HELPER
 # undef ZEND_VM_INTERRUPT
+# undef ZEND_VM_ENTER_EX
+# undef ZEND_VM_LEAVE
 
 # define ZEND_VM_TAIL_CALL(call)               ZEND_MUSTTAIL return call
 # define ZEND_VM_CONTINUE()                    ZEND_VM_TAIL_CALL(opline->handler(ZEND_OPCODE_HANDLER_ARGS_PASSTHRU))
@@ -53468,6 +53470,8 @@ static ZEND_OPCODE_HANDLER_RET ZEND_OPCODE_HANDLER_FUNC_CCONV ZEND_NULL_HANDLER(
     } while (0)
 # define ZEND_VM_DISPATCH_TO_LEAVE_HELPER(helper) opline = &call_leave_op; SAVE_OPLINE(); ZEND_VM_CONTINUE()
 # define ZEND_VM_INTERRUPT()        ZEND_VM_TAIL_CALL(zend_interrupt_helper_SPEC_TAILCALL(ZEND_OPCODE_HANDLER_ARGS_PASSTHRU))
+# define ZEND_VM_ENTER_EX() ZEND_VM_INTERRUPT_CHECK(); ZEND_VM_CONTINUE()
+# define ZEND_VM_LEAVE()    ZEND_VM_CONTINUE()
 
 static ZEND_OPCODE_HANDLER_RET ZEND_OPCODE_HANDLER_CCONV zend_interrupt_helper_SPEC_TAILCALL(ZEND_OPCODE_HANDLER_ARGS);
 static ZEND_OPCODE_HANDLER_RET ZEND_OPCODE_HANDLER_CCONV ZEND_NULL_TAILCALL_HANDLER(ZEND_OPCODE_HANDLER_ARGS);
diff --git a/Zend/zend_vm_gen.php b/Zend/zend_vm_gen.php
index f8989b2336f47..ed0256832d589 100755
--- a/Zend/zend_vm_gen.php
+++ b/Zend/zend_vm_gen.php
@@ -2126,6 +2126,8 @@ function gen_executor($f, $skl, $spec, $kind, $executor_name, $initializer_name)
                         out($f,"# undef ZEND_VM_RETURN\n");
                         out($f,"# undef ZEND_VM_DISPATCH_TO_HELPER\n");
                         out($f,"# undef ZEND_VM_INTERRUPT\n");
+                        out($f,"# undef ZEND_VM_ENTER_EX\n");
+                        out($f,"# undef ZEND_VM_LEAVE\n");
                         out($f,"\n");
                         out($f,"# define ZEND_VM_TAIL_CALL(call)               ZEND_MUSTTAIL return call\n");
                         out($f,"# define ZEND_VM_CONTINUE()                    ZEND_VM_TAIL_CALL(opline->handler(ZEND_OPCODE_HANDLER_ARGS_PASSTHRU))\n");
@@ -2137,6 +2139,8 @@ function gen_executor($f, $skl, $spec, $kind, $executor_name, $initializer_name)
                         out($f,"    } while (0)\n");
                         out($f,"# define ZEND_VM_DISPATCH_TO_LEAVE_HELPER(helper) opline = &call_leave_op; SAVE_OPLINE(); ZEND_VM_CONTINUE()\n");
                         out($f,"# define ZEND_VM_INTERRUPT()        ZEND_VM_TAIL_CALL(zend_interrupt_helper".($spec?"_SPEC":"")."_TAILCALL(ZEND_OPCODE_HANDLER_ARGS_PASSTHRU))\n");
+                        out($f,"# define ZEND_VM_ENTER_EX() ZEND_VM_INTERRUPT_CHECK(); ZEND_VM_CONTINUE()\n");
+                        out($f,"# define ZEND_VM_LEAVE()    ZEND_VM_CONTINUE()\n");
                         out($f,"\n");
                         out($f,"static ZEND_OPCODE_HANDLER_RET ZEND_OPCODE_HANDLER_CCONV zend_interrupt_helper".($spec?"_SPEC":"")."_TAILCALL(ZEND_OPCODE_HANDLER_ARGS);\n");
                         out($f,"static ZEND_OPCODE_HANDLER_RET ZEND_OPCODE_HANDLER_CCONV ZEND_NULL_TAILCALL_HANDLER(ZEND_OPCODE_HANDLER_ARGS);\n");
diff --git a/ext/dba/libinifile/inifile.c b/ext/dba/libinifile/inifile.c
index c5467396d4bfe..6221c7f7a6e71 100644
--- a/ext/dba/libinifile/inifile.c
+++ b/ext/dba/libinifile/inifile.c
@@ -249,7 +249,7 @@ val_type inifile_fetch(inifile *dba, const key_type *key, int skip) {
 		ln.key.group = estrdup(dba->next.key.group);
 	} else {
 		/* specific instance or not same key -> restart search */
-		/* the slow way: restart and seacrch */
+		/* the slow way: restart and search */
 		php_stream_rewind(dba->fp);
 		inifile_line_free(&dba->next);
 	}
@@ -471,7 +471,7 @@ static int inifile_delete_replace_append(inifile *dba, const key_type *key, cons
 	 * 8) Append temporary stream
 	 */
 
-	assert(!append || (key->name && value)); /* missuse */
+	assert(!append || (key->name && value)); /* misuse */
 
 	/* 1 - 3 */
 	inifile_find_group(dba, key, &pos_grp_start);
diff --git a/ext/xsl/tests/gh21496.phpt b/ext/xsl/tests/gh21496.phpt
new file mode 100644
index 0000000000000..7a5cea37937d0
--- /dev/null
+++ b/ext/xsl/tests/gh21496.phpt
@@ -0,0 +1,32 @@
+--TEST--
+GH-21496 (UAF in dom_objects_free_storage when importing non-document node as stylesheet)
+--EXTENSIONS--
+dom
+xsl
+--CREDITS--
+YuanchengJiang
+--FILE--
+<?php
+$comment = new DOMComment("my value");
+$doc = new DOMDocument();
+$doc->loadXML(<<<XML
+<container/>
+XML);
+$doc->documentElement->appendChild($comment);
+unset($doc);
+$proc = new XSLTProcessor();
+var_dump($proc->importStylesheet($comment));
+$sxe = simplexml_load_string('<container/>');
+$proc = new XSLTProcessor();
+$proc->importStylesheet($sxe);
+?>
+--EXPECTF--
+Warning: XSLTProcessor::importStylesheet(): compilation error: file %s line 1 element container in %s on line %d
+
+Warning: XSLTProcessor::importStylesheet(): xsltParseStylesheetProcess : document is not a stylesheet in %s on line %d
+bool(false)
+
+Warning: XSLTProcessor::importStylesheet(): compilation error: element container in %s on line %d
+
+Warning: XSLTProcessor::importStylesheet(): xsltParseStylesheetProcess : document is not a stylesheet in %s on line %d
+
diff --git a/ext/xsl/xsltprocessor.c b/ext/xsl/xsltprocessor.c
index 823c56f1cfb57..d06d008176172 100644
--- a/ext/xsl/xsltprocessor.c
+++ b/ext/xsl/xsltprocessor.c
@@ -167,7 +167,7 @@ PHP_METHOD(XSLTProcessor, importStylesheet)
 	xsltStylesheetPtr sheetp;
 	bool clone_docu = false;
 	xmlNode *nodep = NULL;
-	zval *cloneDocu, rv, clone_zv;
+	zval *cloneDocu, rv, clone_zv, owner_zv;
 	zend_string *member;
 
 	id = ZEND_THIS;
@@ -175,10 +175,40 @@ PHP_METHOD(XSLTProcessor, importStylesheet)
 		RETURN_THROWS();
 	}
 
+	nodep = php_libxml_import_node(docp);
+	if (nodep == NULL) {
+		zend_argument_type_error(1, "must be a valid XML node");
+		RETURN_THROWS();
+	}
+
+	if (Z_OBJ_HANDLER_P(docp, clone_obj) == NULL) {
+		zend_argument_type_error(1, "must be a cloneable node");
+		RETURN_THROWS();
+	}
+
+	ZVAL_UNDEF(&owner_zv);
+
+	/* For non-document nodes, resolve the ownerDocument and clone that
+	 * instead as xsltParseStylesheetProcess may free nodes in the document. */
+	if (nodep->type != XML_DOCUMENT_NODE && nodep->type != XML_HTML_DOCUMENT_NODE) {
+		if (nodep->doc == NULL) {
+			zend_argument_value_error(1, "must be part of a document");
+			RETURN_THROWS();
+		}
+
+		/* See dom_import_simplexml_common */
+
+		dom_object *nodeobj = (dom_object *) ((char *) Z_OBJ_P(docp) - Z_OBJ_HT_P(docp)->offset);
+
+		php_dom_create_object((xmlNodePtr) nodep->doc, &owner_zv, nodeobj);
+		docp = &owner_zv;
+	}
+
 	/* libxslt uses _private, so we must copy the imported
 	 * stylesheet document otherwise the node proxies will be a mess.
 	 * We will clone the object and detach the libxml internals later. */
 	zend_object *clone = Z_OBJ_HANDLER_P(docp, clone_obj)(Z_OBJ_P(docp));
+	zval_ptr_dtor(&owner_zv);
 	if (!clone) {
 		RETURN_THROWS();
 	}