diff --git a/backport-CVE-2025-6021.patch b/backport-CVE-2025-6021.patch
new file mode 100644
index 0000000000000000000000000000000000000000..91d7b567d2f17f18920cb5e923c31c3639759631
--- /dev/null
+++ b/backport-CVE-2025-6021.patch
@@ -0,0 +1,47 @@
+From acbbeef9f5dcdcc901c5f3fa14d583ef8cfd22f0 Mon Sep 17 00:00:00 2001
+From: Nick Wellnhofer <wellnhofer@aevum.de>
+Date: Tue, 27 May 2025 12:53:17 +0200
+Subject: [PATCH] tree: Fix integer overflow in xmlBuildQName
+
+This issue affects memory safety and might receive a CVE ID later.
+
+Fixes #926.
+---
+ tree.c | 9 ++++++---
+ 1 file changed, 6 insertions(+), 3 deletions(-)
+
+diff --git a/tree.c b/tree.c
+index 8910dd8..e207f12 100644
+--- a/tree.c
++++ b/tree.c
+@@ -23,6 +23,7 @@
+ #include <limits.h>
+ #include <ctype.h>
+ #include <stdlib.h>
++#include <stdint.h>
+ 
+ #ifdef LIBXML_ZLIB_ENABLED
+ #include <zlib.h>
+@@ -221,16 +222,18 @@ xmlGetParameterEntityFromDtd(const xmlDtd *dtd, const xmlChar *name) {
+ xmlChar *
+ xmlBuildQName(const xmlChar *ncname, const xmlChar *prefix,
+ 	      xmlChar *memory, int len) {
+-    int lenn, lenp;
++    size_t lenn, lenp;
+     xmlChar *ret;
+ 
+-    if (ncname == NULL) return(NULL);
++    if ((ncname == NULL) || (len < 0)) return(NULL);
+     if (prefix == NULL) return((xmlChar *) ncname);
+ 
+     lenn = strlen((char *) ncname);
+     lenp = strlen((char *) prefix);
++    if (lenn >= SIZE_MAX - lenp - 1)
++        return(NULL);
+ 
+-    if ((memory == NULL) || (len < lenn + lenp + 2)) {
++    if ((memory == NULL) || ((size_t) len < lenn + lenp + 2)) {
+ 	ret = (xmlChar *) xmlMallocAtomic(lenn + lenp + 2);
+ 	if (ret == NULL) {
+ 	    xmlTreeErrMemory("building QName");
+
diff --git a/libxml2.spec b/libxml2.spec
index 4497ea275df9dbc5a4c0ed5f4f6e61f5f8180641..2a112d2c1eb6e989d61062287191d32417b2f38e 100644
--- a/libxml2.spec
+++ b/libxml2.spec
@@ -1,7 +1,7 @@
 Summary: Library providing XML and HTML support
 Name: libxml2
 Version: 2.11.9
-Release: 3
+Release: 4
 License: MIT
 Group: Development/Libraries
 Source: https://download.gnome.org/sources/%{name}/2.11/%{name}-%{version}.tar.xz
@@ -15,6 +15,7 @@ Patch5: backport-CVE-2025-24928.patch
 Patch6: backport-CVE-2025-27113.patch
 Patch7: backport-CVE-2025-32414.patch
 Patch8: backport-CVE-2025-32415.patch
+Patch9: backport-CVE-2025-6021.patch
 
 BuildRequires: python3-devel
 BuildRequires: zlib-devel
@@ -152,6 +153,9 @@ gzip -9 -c doc/libxml2-api.xml > doc/libxml2-api.xml.gz
 
 
 %changelog
+* Sat Jun 14 2025 Funda Wang <fundawang@yeah.net> - 2.11.9-4
+- fix CVE-2025-6021
+
 * Mon Apr 14 2025 Funda Wang <fundawang@yeah.net> - 2.11.9-3
 - fix CVE-2025-32414, CVE-2025-32415