CVE-2024-45490 is a critical security vulnerability identified in libexpat, a widely used XML parsing library, affecting all versions prior to 2.6.3. The root cause is that the function XML_ParseBuffer in xmlparse.c does not properly validate the length parameter, allowing a negative length to be passed without rejection. This improper input validation leads to an integer overflow or buffer overflow condition (classified under CWE-190: Integer Overflow or Wraparound). Because libexpat is often embedded in numerous applications and systems for XML processing, this vulnerability can be exploited remotely without any authentication or user interaction, as indicated by the CVSS vector (AV:N/AC:L/PR:N/UI:N). Successful exploitation can result in complete compromise of confidentiality, integrity, and availability of the affected system, potentially enabling remote code execution or causing denial of service. No known exploits are currently reported in the wild, but the critical severity and ease of exploitation make this a high-risk issue. The vulnerability was published on August 30, 2024, and no official patches were linked at the time of reporting, but upgrading to libexpat 2.6.3 or later is the recommended fix. This vulnerability impacts any software or system that relies on libexpat for XML parsing, including web servers, network appliances, embedded devices, and enterprise applications.

The impact of CVE-2024-45490 on European organizations is significant due to the widespread use of libexpat in various software products and infrastructure components. Exploitation can lead to remote code execution, allowing attackers to gain full control over affected systems, steal sensitive data, disrupt services, or pivot within networks. Critical sectors such as finance, telecommunications, healthcare, and government agencies that process XML data are particularly at risk. The vulnerability's ability to be exploited without authentication or user interaction increases the attack surface and potential for automated attacks. Disruption of availability could affect essential services, while breaches of confidentiality and integrity could lead to data leaks, fraud, or manipulation of critical information. The lack of known exploits currently provides a window for proactive mitigation, but the high CVSS score indicates that the threat could rapidly escalate if weaponized.

1. Immediately upgrade libexpat to version 2.6.3 or later where the vulnerability is fixed. 2. Conduct an inventory of all software and systems using libexpat to identify affected components. 3. Implement input validation and sanitization on XML data sources to detect and block malformed or suspicious payloads that could exploit negative length parsing. 4. Employ network-level protections such as Web Application Firewalls (WAFs) with custom rules to detect anomalous XML parsing requests. 5. Monitor logs and network traffic for unusual XML parsing errors or crashes that may indicate exploitation attempts. 6. Coordinate with software vendors to obtain patches or mitigations if libexpat is embedded in third-party products. 7. Apply defense-in-depth strategies including endpoint protection and network segmentation to limit attacker movement if exploitation occurs. 8. Prepare incident response plans specifically addressing potential exploitation of XML parsing vulnerabilities.