diff --git a/meta/recipes-core/expat/expat/CVE-2026-56411.patch b/meta/recipes-core/expat/expat/CVE-2026-56411.patch
new file mode 100644
index 0000000000..819638ca22
--- /dev/null
+++ b/meta/recipes-core/expat/expat/CVE-2026-56411.patch
@@ -0,0 +1,50 @@
+From 5e696e78f8c4a709c4f774973b142e57090c4364 Mon Sep 17 00:00:00 2001
+From: netliomax25-code <netliomax25@gmail.com>
+Date: Tue, 2 Jun 2026 13:13:34 +0530
+Subject: [PATCH 11/17] xmlwf: protect notation list allocation from integer
+ overflow
+
+CVE: CVE-2026-56411
+Upstream-Status: Backport [https://github.com/libexpat/libexpat/commit/528a4e5017e1bd3b48b689fd0c131df940ae3ea5]
+
+Backport Changes:
+- Use Scarthgap 2.6.4 freeNotations cleanup and return directly
+  because the newer shared cleanUp label is absent.
+
+(cherry picked from commit 528a4e5017e1bd3b48b689fd0c131df940ae3ea5)
+Signed-off-by: Deepak Rathore <deeratho@cisco.com>
+---
+ expat/xmlwf/xmlwf.c | 12 ++++++++++--
+ 1 file changed, 10 insertions(+), 2 deletions(-)
+
+diff --git a/expat/xmlwf/xmlwf.c b/expat/xmlwf/xmlwf.c
+index bd5f68a4..6a3d31b7 100644
+--- a/expat/xmlwf/xmlwf.c
++++ b/expat/xmlwf/xmlwf.c
+@@ -387,9 +387,9 @@ static void XMLCALL
+ endDoctypeDecl(void *userData) {
+   XmlwfUserData *data = (XmlwfUserData *)userData;
+   NotationList **notations;
+-  int notationCount = 0;
++  size_t notationCount = 0;
+   NotationList *p;
+-  int i;
++  size_t i;
+ 
+   /* How many notations do we have? */
+   for (p = data->notationListHead; p != NULL; p = p->next)
+@@ -401,6 +401,14 @@ endDoctypeDecl(void *userData) {
+     return;
+   }
+ 
++  /* Detect and prevent integer overflow in the multiplication, mirroring
++     the guards in xcsdup() and resolveSystemId() */
++  if (notationCount > SIZE_MAX / sizeof(NotationList *)) {
++    fprintf(stderr, "Unable to sort notations");
++    freeNotations(data);
++    return;
++  }
++
+   notations = malloc(notationCount * sizeof(NotationList *));
+   if (notations == NULL) {
+     fprintf(stderr, "Unable to sort notations");
diff --git a/meta/recipes-core/expat/expat_2.6.4.bb b/meta/recipes-core/expat/expat_2.6.4.bb
index 8d7a19e79d..3a880882ae 100644
--- a/meta/recipes-core/expat/expat_2.6.4.bb
+++ b/meta/recipes-core/expat/expat_2.6.4.bb
@@ -61,6 +61,7 @@ SRC_URI = "${GITHUB_BASE_URI}/download/R_${VERSION_TAG}/expat-${PV}.tar.bz2  \
            file://CVE-2026-56406-dependent.patch;striplevel=2 \
            file://CVE-2026-56406.patch;striplevel=2 \
            file://CVE-2026-56409.patch;striplevel=2 \
+           file://CVE-2026-56411.patch;striplevel=2 \
            "
 
 GITHUB_BASE_URI = "https://github.com/libexpat/libexpat/releases/"