libxml2: fix CVE-2025-49795

A NULL pointer dereference vulnerability was found in libxml2 when
processing XPath XML expressions. This flaw allows an attacker to
craft a malicious XML input to libxml2, leading to a denial of service.

Pick commit from 2.13 branch

Reference:
https://security-tracker.debian.org/tracker/CVE-2025-49795

Upstream-patch:
https://gitlab.gnome.org/GNOME/libxml2/-/commit/62048278a4c5fdf14d287dfb400005c0a0caa69f

(From OE-Core rev: 9f17e0911eeb49e007de8ee3e50d9f3f38e08a26)

Signed-off-by: Divya Chellam <divya.chellam@windriver.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>

2 files changed, 76 insertions, 0 deletions

diff --git a/meta/recipes-core/libxml/libxml2/CVE-2025-49795.patch b/meta/recipes-core/libxml/libxml2/CVE-2025-49795.patch
new file mode 100644
index 0000000000..11f543cb9b
--- /dev/null
+++ b/meta/recipes-core/libxml/libxml2/CVE-2025-49795.patch
@@ -0,0 +1,75 @@
+From 62048278a4c5fdf14d287dfb400005c0a0caa69f Mon Sep 17 00:00:00 2001
+From: Michael Mann <mmann78@netscape.net>
+Date: Sat, 21 Jun 2025 12:11:30 -0400
+Subject: [PATCH] [CVE-2025-49795] schematron: Fix null pointer dereference
+ leading to DoS
+
+Fixes #932
+
+CVE: CVE-2025-49795
+
+Upstream-Status: Backport [https://gitlab.gnome.org/GNOME/libxml2/-/commit/62048278a4c5fdf14d287dfb400005c0a0caa69f]
+
+Signed-off-by: Divya Chellam <divya.chellam@windriver.com>
+---
+ result/schematron/zvon16_0.err | 3 +++
+ schematron.c                   | 5 +++++
+ test/schematron/zvon16.sct     | 7 +++++++
+ test/schematron/zvon16_0.xml   | 5 +++++
+ 4 files changed, 20 insertions(+)
+ create mode 100644 result/schematron/zvon16_0.err
+ create mode 100644 test/schematron/zvon16.sct
+ create mode 100644 test/schematron/zvon16_0.xml
+
+diff --git a/result/schematron/zvon16_0.err b/result/schematron/zvon16_0.err
+new file mode 100644
+index 0000000..3d05240
+--- /dev/null
++++ b/result/schematron/zvon16_0.err
+@@ -0,0 +1,3 @@
++XPath error : Unregistered function
++./test/schematron/zvon16_0.xml:2: element book: schematron error : /library/book line 2: Book 
++./test/schematron/zvon16_0.xml fails to validate
+diff --git a/schematron.c b/schematron.c
+index 426300c..6e2ceeb 100644
+--- a/schematron.c
++++ b/schematron.c
+@@ -1509,6 +1509,11 @@ xmlSchematronFormatReport(xmlSchematronValidCtxtPtr ctxt,
+             select = xmlGetNoNsProp(child, BAD_CAST "select");
+             comp = xmlXPathCtxtCompile(ctxt->xctxt, select);
+             eval = xmlXPathCompiledEval(comp, ctxt->xctxt);
++            if (eval == NULL) {
++                xmlXPathFreeCompExpr(comp);
++                xmlFree(select);
++                return ret;
++            }
+ 
+             switch (eval->type) {
+             case XPATH_NODESET: {
+diff --git a/test/schematron/zvon16.sct b/test/schematron/zvon16.sct
+new file mode 100644
+index 0000000..f03848a
+--- /dev/null
++++ b/test/schematron/zvon16.sct
+@@ -0,0 +1,7 @@
++<sch:schema xmlns:sch="http://purl.oclc.org/dsdl/schematron">
++       <sch:pattern id="TestPattern">
++               <sch:rule context="book">
++                       <sch:report test="not(@available)">Book <sch:value-of select="falae()"/> test</sch:report>
++               </sch:rule>
++       </sch:pattern>
++</sch:schema>
+diff --git a/test/schematron/zvon16_0.xml b/test/schematron/zvon16_0.xml
+new file mode 100644
+index 0000000..551e2d6
+--- /dev/null
++++ b/test/schematron/zvon16_0.xml
+@@ -0,0 +1,5 @@
++<library>
++       <book title="Test Book" id="bk101">
++               <author>Test Author</author>
++       </book>
++</library>
+-- 
+2.40.0
+
diff --git a/meta/recipes-core/libxml/libxml2_2.13.8.bb b/meta/recipes-core/libxml/libxml2_2.13.8.bb
index 3d6ecf5458..fd042c311d 100644
--- a/meta/recipes-core/libxml/libxml2_2.13.8.bb
+++ b/meta/recipes-core/libxml/libxml2_2.13.8.bb
@@ -19,6 +19,7 @@ SRC_URI += "http://www.w3.org/XML/Test/xmlts20130923.tar;subdir=${BP};name=testt
            file://install-tests.patch \
            file://CVE-2025-6021.patch \
            file://CVE-2025-49794_CVE-2025-49796.patch \
+           file://CVE-2025-49795.patch \
            "
 
 SRC_URI[archive.sha256sum] = "277294cb33119ab71b2bc81f2f445e9bc9435b893ad15bb2cd2b0e859a0ee84a"