CVE-2025-32415: Xmlsoft Libxml2 Buffer Overflow Flaw

CVE-2025-32415 Overview

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. This vulnerability could lead to a denial of service due to application crash.

Critical Impact
This vulnerability allows potential denial of service via crafted XML documents.

Affected Products

Xmlsoft libxml2
Not Available
Not Available

Discovery Timeline

Not Available - Vulnerability discovered by Not Available
Not Available - Responsible disclosure to xmlsoft
Not Available - CVE CVE-2025-32415 assigned
Not Available - xmlsoft releases security patch
2025-04-17 - CVE CVE-2025-32415 published to NVD
2025-11-03 - Last updated in NVD database

Technical Details for CVE-2025-32415

Vulnerability Analysis

The vulnerability is caused by improper handling of identity constraints in XML schema, leading to a heap-based buffer under-read. This can cause an application to crash when handling specially crafted XML documents.

Root Cause

The root cause lies in the xmlSchemaIDCFillNodeTables function of xmlschemas.c, where incorrect assumptions about buffer size result in memory under-read.

Attack Vector

This issue can be exploited remotely by sending a crafted XML document over a network to an application using a vulnerable version of libxml2 for schema validation.

// Example exploitation code (sanitized)
#include <libxml/xmlschemas.h>
int main() {
    xmlSchemaParserCtxtPtr ctxt;
    ctxt = xmlSchemaNewParserCtxt("crafted_schema.xsd");
    if (ctxt == NULL) return -1;
    // Further setup and triggering operations
    return 0;
}

Detection Methods for CVE-2025-32415

Indicators of Compromise

Abnormal application crashes
Unexpected application exits
Memory access violation logs

Detection Strategies

Monitor application logs for crashes or abnormal terminations when processing XML data with schemas. Use tools to check XML handling for security issues.

Monitoring Recommendations

Implement network-level monitoring for large or unusual XML documents sent to applications that utilize libxml2. Enable crash dumps and analyze them for patterns consistent with buffer under-read.

How to Mitigate CVE-2025-32415

Immediate Actions Required

Upgrade to libxml2 version 2.13.8 or later.
Disable processing of untrusted XML schemas.
Implement input validation strategies.

Patch Information

Upgrading libxml2 to version 2.13.8 or 2.14.2 directly addresses this vulnerability. Ensure all applications linked to libxml2 are updated.

Workarounds

For applications that cannot be updated immediately, consider disabling XML schema validation or sandboxing processes that handle XML data.

bash

# Configuration example
export XML_CATALOG_FILES="structured_catalog.xml"
# Set secure paths for schema validation