Overview
The CVE-2025-49795 is a major vulnerability found within libxml2, an XML parsing library commonly used in information systems and web services. The vulnerability, a NULL pointer dereference, can be exploited to trigger a denial of service attack, potentially compromising systems or leading to data leakage.
Vulnerability Summary
CVE ID: CVE-2025-49795
Severity: High (7.5 CVSS)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: Denial of Service; possible system compromise and data leakage
Affected Products
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Product | Affected Versions
libxml2 | All versions up to the latest patch
How the Exploit Works
The vulnerability exists within the XPath processing module of the libxml2 library. An attacker can craft a malicious XML input designed to cause a NULL pointer dereference when parsed by libxml2. This results in a service disruption, causing a denial of service. If the attacker’s input is crafted with precise knowledge of the system’s memory layout, it could potentially even lead to arbitrary code execution.
Conceptual Example Code
POST /xml/parse HTTP/1.1
Host: target.example.com
Content-Type: application/xml
<root>
<exploit>{{NULL_POINTER}}</exploit>
</root>
In this conceptual example, the attacker sends a POST request to a vulnerable endpoint, embedding the malicious payload within the XML data. The payload, represented here symbolically as {{NULL_POINTER}}, is designed to trigger the NULL pointer dereference in libxml2.

