CVE-2025-59375 is a high-severity vulnerability identified in the libexpat XML parsing library, specifically in versions prior to 2.7.2. The vulnerability is classified under CWE-770, which pertains to the allocation of resources without limits or throttling. In this case, libexpat allows attackers to trigger excessively large dynamic memory allocations by submitting a crafted, yet small XML document for parsing. This behavior can lead to resource exhaustion on the target system, resulting in denial of service (DoS) conditions. The vulnerability is exploitable remotely over the network without requiring any authentication or user interaction, as indicated by the CVSS vector (AV:N/AC:L/PR:N/UI:N). The impact is limited to availability, with no confidentiality or integrity loss reported. The exploitability is high due to the low attack complexity and no prerequisites. Although no known exploits are currently in the wild, the vulnerability poses a significant risk to any application or system that relies on vulnerable versions of libexpat for XML parsing. Since libexpat is widely used in many software products and platforms, the scope of affected systems is broad. The vulnerability was published on September 15, 2025, and no official patches or mitigation links are provided yet, emphasizing the need for prompt attention once updates become available.

For European organizations, the impact of CVE-2025-59375 can be substantial, especially for those relying on software stacks that incorporate libexpat for XML processing. The vulnerability can be exploited to cause denial of service by exhausting system memory, potentially disrupting critical services such as web servers, middleware, and applications that parse XML data. This can affect sectors including finance, healthcare, telecommunications, and government services, where availability is crucial. Disruptions could lead to operational downtime, loss of productivity, and damage to reputation. Additionally, organizations with strict regulatory requirements around service availability and incident response may face compliance challenges if affected by this vulnerability. The lack of authentication and user interaction requirements means attackers can launch attacks remotely and at scale, increasing the risk of widespread service outages.

To mitigate CVE-2025-59375 effectively, European organizations should: 1) Identify and inventory all software and systems that use libexpat, including indirect dependencies in third-party applications. 2) Monitor vendor advisories closely for the release of libexpat version 2.7.2 or later, which addresses this vulnerability, and plan for immediate patching upon availability. 3) Implement network-level protections such as rate limiting and input validation to detect and block suspicious XML payloads that could trigger excessive memory allocation. 4) Employ application-layer firewalls or XML gateways capable of enforcing limits on XML document size and complexity to prevent resource exhaustion attacks. 5) Conduct thorough testing of XML processing components under load to identify potential resource exhaustion scenarios. 6) Establish robust monitoring and alerting for unusual memory usage patterns in services that parse XML. 7) Where immediate patching is not feasible, consider isolating vulnerable services or limiting their exposure to untrusted networks to reduce attack surface.