CVE-2025-49794 is a use-after-free vulnerability identified in libxml2, a widely used XML parsing library, specifically triggered when parsing XPath elements within XML schematron documents containing <sch:name path="..."/> schema elements. The flaw arises due to improper handling of pointer lifetimes during the parsing process, leading to dereferencing of expired pointers. This memory corruption can cause the affected program to crash or exhibit undefined behavior, which may be leveraged by attackers to disrupt services or potentially execute arbitrary code, although no confirmed exploits exist yet. The vulnerability affects Red Hat Enterprise Linux 10, which bundles libxml2 as a core component. The CVSS 3.1 score of 9.1 indicates a critical severity with network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), unchanged scope (S:U), no confidentiality impact (C:N), but high integrity (I:H) and availability (A:H) impacts. This means an attacker can remotely send malicious XML input to vulnerable applications using libxml2, causing denial of service or potentially more severe consequences. The vulnerability was published on June 16, 2025, with no known exploits in the wild at this time. The root cause is a use-after-free condition during XPath parsing in schematron processing, a specialized XML validation technique. Given libxml2's widespread use in many software products and services, this vulnerability poses a significant risk to systems processing untrusted XML data, especially in server-side applications, middleware, and enterprise environments.

For European organizations, the impact of CVE-2025-49794 is significant, particularly for those relying on Red Hat Enterprise Linux 10 and applications that process XML data using libxml2. The vulnerability can lead to denial of service through application crashes, disrupting critical business operations and services. In environments where XML processing is integral, such as financial services, telecommunications, government services, and industrial control systems, this can cause operational downtime and loss of service availability. Although no confirmed code execution exploits exist, the potential for undefined behavior raises concerns about integrity and possible escalation. The lack of required privileges or user interaction means attackers can exploit this remotely, increasing the threat surface. European organizations with public-facing services or internal systems parsing XML from untrusted sources are particularly vulnerable. Additionally, the disruption caused by crashes could impact compliance with regulations requiring high availability and data integrity, such as GDPR and NIS Directive mandates.

To mitigate CVE-2025-49794, organizations should prioritize applying official patches from Red Hat as soon as they are released. Until patches are available, restrict or sanitize XML input sources to only trusted origins to reduce exposure. Employ application-layer filtering or XML schema validation to detect and block malicious schematron elements containing <sch:name path="..."/> constructs. Consider deploying runtime memory protection tools such as AddressSanitizer or similar to detect use-after-free conditions during testing and staging. Review and update XML processing workflows to minimize reliance on schematron validation where possible. Implement network-level protections like Web Application Firewalls (WAFs) with custom rules to detect anomalous XML payloads. Monitor application logs and system behavior for crashes or anomalies indicative of exploitation attempts. Finally, maintain an inventory of software components using libxml2 to ensure all affected systems are identified and remediated promptly.