From 402b662716adaf18da652504153b8ac737c78cf7 Mon Sep 17 00:00:00 2001
From: lamtung-monash <lam.nguyentung@monash.edu>
Date: Tue, 16 Dec 2025 16:57:53 +0800
Subject: [PATCH] Fix memory leak in xmlParseBalancedChunkMemoryRecover

When doc is NULL, namespace created in xmlTreeEnsureXMLDecl is bind to newDoc->oldNs, in this case, set newDoc->oldNs to NULL and free newDoc will cause a memory leak.
---
 libxml2-2.9.9/parser.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/libxml2-2.9.9/parser.c b/libxml2-2.9.9/parser.c
index 5813a6643..d12d9e8c4 100644
--- a/libxml2-2.9.9/parser.c
+++ b/libxml2-2.9.9/parser.c
@@ -13898,6 +13898,7 @@ xmlParseBalancedChunkMemoryRecover(xmlDocPtr doc, xmlSAXHandlerPtr sax,
     xmlFreeParserCtxt(ctxt);
     newDoc->intSubset = NULL;
     newDoc->extSubset = NULL;
+    if(doc != NULL)
     newDoc->oldNs = NULL;
     xmlFreeDoc(newDoc);