CVE-2024-55549 is a use-after-free vulnerability identified in the libxslt library, a widely used XML stylesheet transformation library. The vulnerability exists in the xsltGetInheritedNsList function, which is responsible for managing inherited XML namespace lists during XSLT processing. The flaw occurs due to improper handling of namespace prefixes when excluding certain result prefixes, leading to a use-after-free condition. This memory corruption can be exploited to alter the integrity of the process or cause denial of service by crashing the application. The vulnerability affects all versions of libxslt prior to 1.1.43. According to the CVSS 3.1 vector, the attack requires local access (AV:L), high attack complexity (AC:H), no privileges (PR:N), and no user interaction (UI:N). The scope is changed (S:C), indicating that exploitation can affect resources beyond the vulnerable component. The impact metrics show no confidentiality loss (C:N), but high integrity (I:H) and availability (A:H) impacts, meaning attackers can manipulate or disrupt the affected processes. No known exploits have been reported in the wild yet, but the nature of the vulnerability suggests potential for exploitation in environments where libxslt is used for XML transformations, especially in local or multi-user systems. The vulnerability was reserved in December 2024 and published in March 2025, with no patch links currently available, indicating that remediation may be pending or in progress.

For European organizations, the vulnerability poses a significant risk particularly to those relying on libxslt for XML processing in enterprise applications, middleware, or custom software solutions. Exploitation could lead to process crashes, denial of service, or unauthorized manipulation of XML transformation results, impacting data integrity and service availability. Sectors such as finance, telecommunications, manufacturing, and government services that process large volumes of XML data are at higher risk. The requirement for local access and high attack complexity somewhat limits remote exploitation, but insider threats or compromised local accounts could leverage this vulnerability. Disruption of critical services or data corruption could have cascading effects on business operations and compliance with data integrity regulations such as GDPR. The absence of known exploits reduces immediate risk but does not eliminate the threat, especially as patches are not yet widely available.

Organizations should immediately inventory their software stacks to identify usage of libxslt versions prior to 1.1.43. Where possible, upgrade libxslt to version 1.1.43 or later once patches are released. For embedded or third-party software that bundles libxslt, coordinate with vendors to obtain patched versions or apply mitigations. Implement strict access controls to limit local user privileges and reduce the risk of exploitation by untrusted users. Employ runtime protections such as memory corruption mitigations (e.g., ASLR, DEP) to reduce exploitation success. Monitor system logs and application behavior for crashes or anomalies related to XML processing. Consider isolating XML processing workloads in sandboxed environments to contain potential impacts. Maintain up-to-date backups and incident response plans to quickly recover from potential denial-of-service or integrity incidents.