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.

Signed-off-by: Roland Kovacs <roland.kovacs@est.tech>
Signed-off-by: Steve Sakoman <steve@sakoman.com>

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 (file)
index 0000000..2e21a99
--- /dev/null
+++ b/meta/recipes-core/libxml/libxml2/CVE-2025-49795.patch
@@ -0,0 +1,92 @@
+From 19e0a3ed092085a4d6689397d4f08cf5d86267af Mon Sep 17 00:00:00 2001
+From: Michael Mann <mmann78@netscape.net>
+Date: Sat, 21 Jun 2025 12:11:30 -0400
+Subject: [PATCH] Schematron: Fix null pointer dereference leading to DoS
+
+(CVE-2025-49795)
+
+Fixes #932
+
+Upstream-Status: Backport [https://gitlab.gnome.org/GNOME/libxml2/-/commit/c24909ba2601848825b49a60f988222da3019667]
+CVE: CVE-2025-49795
+
+(cherry picked from commit c24909ba2601848825b49a60f988222da3019667)
+Signed-off-by: Roland Kovacs <roland.kovacs@est.tech>
+---
+ result/schematron/zvon16_0     | 6 ++++++
+ result/schematron/zvon16_0.err | 5 +++++
+ schematron.c                   | 5 +++++
+ test/schematron/zvon16.sct     | 7 +++++++
+ test/schematron/zvon16_0.xml   | 5 +++++
+ 5 files changed, 28 insertions(+)
+ create mode 100644 result/schematron/zvon16_0
+ 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 b/result/schematron/zvon16_0
+new file mode 100644
+index 00000000..768cf6f5
+--- /dev/null
++++ b/result/schematron/zvon16_0
+@@ -0,0 +1,6 @@
++<?xml version="1.0"?>
++<library>
++      <book title="Test Book" id="bk101">
++              <author>Test Author</author>
++      </book>
++</library>
+diff --git a/result/schematron/zvon16_0.err b/result/schematron/zvon16_0.err
+new file mode 100644
+index 00000000..a4fab4c8
+--- /dev/null
++++ b/result/schematron/zvon16_0.err
+@@ -0,0 +1,5 @@
++Pattern: TestPattern
++xmlXPathCompOpEval: function falae not found
++XPath error : Unregistered function
++/library/book line 2: Book 
++./test/schematron/zvon16_0.xml fails to validate
+diff --git a/schematron.c b/schematron.c
+index a8259201..86c63e64 100644
+--- a/schematron.c
++++ b/schematron.c
+@@ -1481,6 +1481,11 @@ 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 00000000..f03848aa
+--- /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 00000000..551e2d65
+--- /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>
+-- 
+2.34.1
+

diff --git a/meta/recipes-core/libxml/libxml2_2.12.10.bb b/meta/recipes-core/libxml/libxml2_2.12.10.bb
index 488ace62e59d1189d3eac6313d4ad82fa4034ed6..c289de6f73034ea990049a493199e57e22662227 100644 (file)
--- a/meta/recipes-core/libxml/libxml2_2.12.10.bb
+++ b/meta/recipes-core/libxml/libxml2_2.12.10.bb
@@ -22,6 +22,7 @@ SRC_URI += "http://www.w3.org/XML/Test/xmlts20130923.tar;subdir=${BP};name=testt
            file://CVE-2025-32415.patch \
            file://CVE-2025-6021.patch \
            file://CVE-2025-49794-CVE-2025-49796.patch \
+           file://CVE-2025-49795.patch \
            "
 
 SRC_URI[archive.sha256sum] = "c3d8c0c34aa39098f66576fe51969db12a5100b956233dc56506f7a8679be995"