DSA-5949-1

xmlXIncludeAddNode in xinclude.c in libxml2 before 2.11.0 has a use-after-free.

Xmlsoft Libxml2 v2.11.0 was discovered to contain an out-of-bounds read via the xmlSAX2StartElement() function at /libxml2/SAX2.c. This vulnerability allows attackers to cause a Denial of Service (DoS) via supplying a crafted XML file. NOTE: the vendor's position is that the product does not support the legacy SAX1 interface with custom callbacks; there is a crash even without crafted input.

libxml2 through 2.11.5 has a use-after-free that can only occur after a certain memory allocation fails. This occurs in xmlUnlinkNode in tree.c. NOTE: the vendor's position is "I don't think these issues are critical enough to warrant a CVE ID ... because an attacker typically can't control when memory allocations fail."

An issue was discovered in libxml2 before 2.11.7 and 2.12.x before 2.12.5. When using the XML Reader interface with DTD validation and XInclude expansion enabled, processing crafted XML documents can lead to an xmlValidatePopElement use-after-free.

An issue was discovered in xmllint (from libxml2) before 2.11.8 and 2.12.x before 2.12.7. Formatting error messages with xmllint --htmlout can result in a buffer over-read in xmlHTMLPrintFileContext in xmllint.c.

libxml2 before 2.12.10 and 2.13.x before 2.13.6 has a use-after-free in xmlSchemaIDCFillNodeTables and xmlSchemaBubbleIDCNodeTables in xmlschemas.c. To exploit this, a crafted XML document must be validated against an XML schema with certain identity constraints, or a crafted XML schema must be used.

libxml2 before 2.12.10 and 2.13.x before 2.13.6 has a stack-based buffer overflow in xmlSnprintfElements in valid.c. To exploit this, DTD validation must occur for an untrusted document or untrusted DTD. NOTE: this is similar to CVE-2017-9047.

libxml2 before 2.12.10 and 2.13.x before 2.13.6 has a NULL pointer dereference in xmlPatMatch in pattern.c.

In libxml2 before 2.13.8 and 2.14.x before 2.14.2, out-of-bounds memory access can occur in the Python API (Python bindings) because of an incorrect return value. This occurs in xmlPythonFileRead and xmlPythonFileReadRaw because of a difference between bytes and characters.

In libxml2 before 2.13.8 and 2.14.x before 2.14.2, xmlSchemaIDCFillNodeTables in xmlschemas.c has a heap-based buffer under-read. To exploit this, a crafted XML document must be validated against an XML schema with certain identity constraints, or a crafted XML schema must be used.