diff --git a/NEWS b/NEWS
index 06ccd818371e0..68128f2128378 100644
--- a/NEWS
+++ b/NEWS
@@ -15,6 +15,7 @@ DOM:
   . Fix cloning attribute with namespace disappearing namespace. (nielsdos)
   . Implement DOM HTML5 parsing and serialization RFC. (nielsdos)
   . Fix DOMElement->prefix with empty string creates bogus prefix. (nielsdos)
+  . Handle OOM more consistently. (nielsdos)
 
 FPM:
   . Implement GH-12385 (flush headers without body when calling flush()).
diff --git a/UPGRADING b/UPGRADING
index b35439e0c2e31..2334b1abbf4e8 100644
--- a/UPGRADING
+++ b/UPGRADING
@@ -25,6 +25,11 @@ PHP 8.4 UPGRADE NOTES
     you might encounter errors if the declaration is incompatible.
     Consult sections 2. New Features and 6. New Functions for a list of
     newly implemented methods and constants.
+  . Some DOM methods previously returned false or a PHP_ERR DOMException if a new
+    node could not be allocated. They consistently throw an INVALID_STATE_ERR
+    DOMException now. This situation is extremely unlikely though and probably
+    will not affect you. As a result DOMImplementation::createDocument() now has
+    a tentative return type of DOMDocument instead of DOMDocument|false.
 
 - PDO_DBLIB:
   . setAttribute, DBLIB_ATTR_STRINGIFY_UNIQUEIDENTIFIER and DBLIB_ATTR_DATETIME_CONVERT
diff --git a/ext/dom/document.c b/ext/dom/document.c
index 8cdf8ec19b02a..e9dc173bb5bfc 100644
--- a/ext/dom/document.c
+++ b/ext/dom/document.c
@@ -842,7 +842,12 @@ PHP_METHOD(DOM_Document, createElementNS)
 	if (errorcode == 0) {
 		if (xmlValidateName((xmlChar *) localname, 0) == 0) {
 			nodep = xmlNewDocNode(docp, NULL, (xmlChar *) localname, (xmlChar *) value);
-			if (nodep != NULL && uri != NULL) {
+			if (UNEXPECTED(nodep == NULL)) {
+				php_dom_throw_error(INVALID_STATE_ERR, /* strict */ true);
+				RETURN_THROWS();
+			}
+
+			if (uri != NULL) {
 				xmlNsPtr nsptr = xmlSearchNsByHref(nodep->doc, nodep, (xmlChar *) uri);
 				if (nsptr == NULL) {
 					nsptr = dom_get_ns(nodep, uri, &errorcode, prefix);
@@ -860,17 +865,11 @@ PHP_METHOD(DOM_Document, createElementNS)
 	}
 
 	if (errorcode != 0) {
-		if (nodep != NULL) {
-			xmlFreeNode(nodep);
-		}
+		xmlFreeNode(nodep);
 		php_dom_throw_error(errorcode, dom_get_strict_error(intern->document));
 		RETURN_FALSE;
 	}
 
-	if (nodep == NULL) {
-		RETURN_FALSE;
-	}
-
 	DOM_RET_OBJ(nodep, &ret, intern);
 }
 /* }}} end dom_document_create_element_ns */
@@ -904,7 +903,12 @@ PHP_METHOD(DOM_Document, createAttributeNS)
 		if (errorcode == 0) {
 			if (xmlValidateName((xmlChar *) localname, 0) == 0) {
 				nodep = (xmlNodePtr) xmlNewDocProp(docp, (xmlChar *) localname, NULL);
-				if (nodep != NULL && uri_len > 0) {
+				if (UNEXPECTED(nodep == NULL)) {
+					php_dom_throw_error(INVALID_STATE_ERR, /* strict */ true);
+					RETURN_THROWS();
+				}
+
+				if (uri_len > 0) {
 					nsptr = xmlSearchNsByHref(nodep->doc, root, (xmlChar *) uri);
 					if (nsptr == NULL || nsptr->prefix == NULL) {
 						nsptr = dom_get_ns(root, uri, &errorcode, prefix ? prefix : "default");
@@ -926,17 +930,11 @@ PHP_METHOD(DOM_Document, createAttributeNS)
 	}
 
 	if (errorcode != 0) {
-		if (nodep != NULL) {
-			xmlFreeProp((xmlAttrPtr) nodep);
-		}
+		xmlFreeProp((xmlAttrPtr) nodep);
 		php_dom_throw_error(errorcode, dom_get_strict_error(intern->document));
 		RETURN_FALSE;
 	}
 
-	if (nodep == NULL) {
-		RETURN_FALSE;
-	}
-
 	DOM_RET_OBJ(nodep, &ret, intern);
 }
 /* }}} end dom_document_create_attribute_ns */
diff --git a/ext/dom/domimplementation.c b/ext/dom/domimplementation.c
index 64432fc3da3ee..d771eccad8684 100644
--- a/ext/dom/domimplementation.c
+++ b/ext/dom/domimplementation.c
@@ -138,6 +138,8 @@ PHP_METHOD(DOMImplementation, createDocument)
 			RETURN_THROWS();
 		}
 		if (doctype->doc != NULL) {
+			/* As the new document is the context node, and the default for strict error checking
+			 * is true, this will always throw. */
 			php_dom_throw_error(WRONG_DOCUMENT_ERR, 1);
 			RETURN_THROWS();
 		}
@@ -172,7 +174,9 @@ PHP_METHOD(DOMImplementation, createDocument)
 		if (localname != NULL) {
 			xmlFree(localname);
 		}
-		RETURN_FALSE;
+		/* See above for strict error checking argument. */
+		php_dom_throw_error(INVALID_STATE_ERR, /* strict */ true);
+		RETURN_THROWS();
 	}
 
 	if (doctype != NULL) {
@@ -195,8 +199,7 @@ PHP_METHOD(DOMImplementation, createDocument)
 			}
 			xmlFreeDoc(docp);
 			xmlFree(localname);
-			/* Need some better type of error here */
-			php_dom_throw_error(PHP_ERR, 1);
+			php_dom_throw_error(INVALID_STATE_ERR, /* strict */ true);
 			RETURN_THROWS();
 		}
 
diff --git a/ext/dom/node.c b/ext/dom/node.c
index fbf1f327e4d34..6d026c6962495 100644
--- a/ext/dom/node.c
+++ b/ext/dom/node.c
@@ -687,7 +687,8 @@ zend_result dom_node_prefix_write(dom_object *obj, zval *newval)
 					(nodep->type == XML_ATTRIBUTE_NODE && zend_string_equals_literal(prefix_str, "xmlns") &&
 					 strcmp(strURI, (char *) DOM_XMLNS_NAMESPACE)) ||
 					(nodep->type == XML_ATTRIBUTE_NODE && !strcmp((char *) nodep->name, "xmlns"))) {
-					ns = NULL;
+					php_dom_throw_error(NAMESPACE_ERR, dom_get_strict_error(obj->document));
+					return FAILURE;
 				} else {
 					curns = nsnode->nsDef;
 					while (curns != NULL) {
@@ -699,14 +700,15 @@ zend_result dom_node_prefix_write(dom_object *obj, zval *newval)
 					}
 					if (ns == NULL) {
 						ns = xmlNewNs(nsnode, nodep->ns->href, (xmlChar *)prefix);
+						/* Sadly, we cannot distinguish between OOM and namespace conflict.
+						 * But OOM will almost never happen. */
+						if (UNEXPECTED(ns == NULL)) {
+							php_dom_throw_error(NAMESPACE_ERR, /* strict */ true);
+							return FAILURE;
+						}
 					}
 				}
 
-				if (ns == NULL) {
-					php_dom_throw_error(NAMESPACE_ERR, dom_get_strict_error(obj->document));
-					return FAILURE;
-				}
-
 				xmlSetNs(nodep, ns);
 			}
 			break;
diff --git a/ext/dom/php_dom.stub.php b/ext/dom/php_dom.stub.php
index 2bd600e0c6e39..dd52d5ca510a5 100644
--- a/ext/dom/php_dom.stub.php
+++ b/ext/dom/php_dom.stub.php
@@ -477,8 +477,8 @@ public function hasFeature(string $feature, string $version): bool {}
         /** @return DOMDocumentType|false */
         public function createDocumentType(string $qualifiedName, string $publicId = "", string $systemId = "") {}
 
-        /** @return DOMDocument|false */
-        public function createDocument(?string $namespace = null, string $qualifiedName = "", ?DOMDocumentType $doctype = null) {}
+        /** @tentative-return-type */
+        public function createDocument(?string $namespace = null, string $qualifiedName = "", ?DOMDocumentType $doctype = null): DOMDocument {}
     }
 
     /** @alias DOM\DocumentFragment */
diff --git a/ext/dom/php_dom_arginfo.h b/ext/dom/php_dom_arginfo.h
index 703db8fa8184c..43de4fee965cb 100644
--- a/ext/dom/php_dom_arginfo.h
+++ b/ext/dom/php_dom_arginfo.h
@@ -1,5 +1,5 @@
 /* This is a generated file, edit the .stub.php file instead.
- * Stub hash: 53f161ae504057211c907938819f6e7f1f4fbfa2 */
+ * Stub hash: dc65484181a06009b064b650edbb9d831a56fd7c */
 
 ZEND_BEGIN_ARG_WITH_RETURN_OBJ_INFO_EX(arginfo_dom_import_simplexml, 0, 1, DOMElement, 0)
 	ZEND_ARG_TYPE_INFO(0, node, IS_OBJECT, 0)
@@ -144,7 +144,7 @@ ZEND_BEGIN_ARG_INFO_EX(arginfo_class_DOMImplementation_createDocumentType, 0, 0,
 	ZEND_ARG_TYPE_INFO_WITH_DEFAULT_VALUE(0, systemId, IS_STRING, 0, "\"\"")
 ZEND_END_ARG_INFO()
 
-ZEND_BEGIN_ARG_INFO_EX(arginfo_class_DOMImplementation_createDocument, 0, 0, 0)
+ZEND_BEGIN_ARG_WITH_TENTATIVE_RETURN_OBJ_INFO_EX(arginfo_class_DOMImplementation_createDocument, 0, 0, DOMDocument, 0)
 	ZEND_ARG_TYPE_INFO_WITH_DEFAULT_VALUE(0, namespace, IS_STRING, 1, "null")
 	ZEND_ARG_TYPE_INFO_WITH_DEFAULT_VALUE(0, qualifiedName, IS_STRING, 0, "\"\"")
 	ZEND_ARG_OBJ_INFO_WITH_DEFAULT_VALUE(0, doctype, DOMDocumentType, 1, "null")
diff --git a/ext/dom/text.c b/ext/dom/text.c
index c51240273d89c..1f2a6443ff40e 100644
--- a/ext/dom/text.c
+++ b/ext/dom/text.c
@@ -152,8 +152,8 @@ PHP_METHOD(DOMText, splitText)
 	xmlFree(second);
 
 	if (nnode == NULL) {
-		/* TODO Add warning? */
-		RETURN_FALSE;
+		php_dom_throw_error(INVALID_STATE_ERR, /* strict */ true);
+		RETURN_THROWS();
 	}
 
 	if (node->parent != NULL) {