[OE-core][wrynose][PATCH v2 03/10] expat: fix CVE-2026-56404

["Deepak Rathore -X (deeratho - E INFOCHIPS PRIVATE LIMITED at Cisco)" <deeratho@cisco.com>]

From: Deepak Rathore <deeratho@cisco.com>

This patch applies the upstream fix shown in [1] as referenced by [2].

[1] https://github.com/libexpat/libexpat/commit/babfc48090977cbf7be24b2c48f6053dca75c164
[2] https://nvd.nist.gov/vuln/detail/CVE-2026-56404

Signed-off-by: Deepak Rathore <deeratho@cisco.com>
---
- Changes from v1 to v2: Refresh the patch on top of
latest wrynose branch merged commits.
 .../expat/expat/CVE-2026-56404.patch          | 47 +++++++++++++++++++
 meta/recipes-core/expat/expat_2.7.5.bb        |  1 +
 2 files changed, 48 insertions(+)
 create mode 100644 meta/recipes-core/expat/expat/CVE-2026-56404.patch

diff --git a/meta/recipes-core/expat/expat/CVE-2026-56404.patch b/meta/recipes-core/expat/expat/CVE-2026-56404.patch
new file mode 100644
index 0000000000..6bca7cf961
--- /dev/null
+++ b/meta/recipes-core/expat/expat/CVE-2026-56404.patch
@@ -0,0 +1,47 @@
+From 8cb4583ac3204175a03c8ea8e371adee583b0bec Mon Sep 17 00:00:00 2001
+From: netliomax25-code <netliomax25@gmail.com>
+Date: Thu, 28 May 2026 12:44:11 +0530
+Subject: [PATCH] lib: protect function addBinding from signed integer overflow
+
+CVE: CVE-2026-56404
+Upstream-Status: Backport [https://github.com/libexpat/libexpat/commit/babfc48090977cbf7be24b2c48f6053dca75c164]
+
+(cherry picked from commit babfc48090977cbf7be24b2c48f6053dca75c164)
+Signed-off-by: Deepak Rathore <deeratho@cisco.com>
+---
+ expat/lib/xmlparse.c | 11 ++++++++++-
+ 1 file changed, 10 insertions(+), 1 deletion(-)
+
+diff --git a/expat/lib/xmlparse.c b/expat/lib/xmlparse.c
+index 53f842d1..33b92c9c 100644
+--- a/expat/lib/xmlparse.c
++++ b/expat/lib/xmlparse.c
+@@ -4485,6 +4485,10 @@ addBinding(XML_Parser parser, PREFIX *prefix, const ATTRIBUTE_ID *attId,
+   }
+ 
+   for (len = 0; uri[len]; len++) {
++    /* Detect and prevent signed integer overflow */
++    if (len == INT_MAX) {
++      return XML_ERROR_NO_MEMORY;
++    }
+     if (isXML && (len > xmlLen || uri[len] != xmlNamespace[len]))
+       isXML = XML_FALSE;
+ 
+@@ -4525,8 +4529,13 @@ addBinding(XML_Parser parser, PREFIX *prefix, const ATTRIBUTE_ID *attId,
+   if (isXMLNS)
+     return XML_ERROR_RESERVED_NAMESPACE_URI;
+ 
+-  if (parser->m_namespaceSeparator)
++  if (parser->m_namespaceSeparator) {
++    /* Detect and prevent signed integer overflow */
++    if (len == INT_MAX) {
++      return XML_ERROR_NO_MEMORY;
++    }
+     len++;
++  }
+   if (parser->m_freeBindingList) {
+     b = parser->m_freeBindingList;
+     if (len > b->uriAlloc) {
+-- 
+2.43.7
+
diff --git a/meta/recipes-core/expat/expat_2.7.5.bb b/meta/recipes-core/expat/expat_2.7.5.bb
index 934cde4b1a..d15e023207 100644
--- a/meta/recipes-core/expat/expat_2.7.5.bb
+++ b/meta/recipes-core/expat/expat_2.7.5.bb
@@ -22,6 +22,7 @@ SRC_URI = "${GITHUB_BASE_URI}/download/R_${VERSION_TAG}/expat-${PV}.tar.bz2  \
            file://CVE-2026-56403_p1.patch;striplevel=2 \
            file://CVE-2026-56403_p2.patch;striplevel=2 \
            file://CVE-2026-56408.patch;striplevel=2 \
+           file://CVE-2026-56404.patch;striplevel=2 \
            "
 
 GITHUB_BASE_URI = "https://github.com/libexpat/libexpat/releases/"
-- 
2.35.6