CVE-2024-12426 is a vulnerability classified under CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor) affecting The Document Foundation's LibreOffice software versions from 24.8 before 24.8.4. The issue arises because URLs embedded within LibreOffice documents can be constructed to include expansions of environmental variables and arbitrary INI file values. When a user opens such a document, these expansions occur, and the resulting data can be exfiltrated to a remote server specified in the URL. This behavior leads to unintended disclosure of potentially sensitive environmental data and configuration values, which may include credentials, system paths, or other confidential information stored in environment variables or INI files. The vulnerability requires the user to open a crafted document, involves low complexity for an attacker with limited privileges (local access), and requires user interaction. The CVSS 4.0 score is 6.7 (medium severity), reflecting the moderate impact on confidentiality and the conditions needed for exploitation. No known exploits have been reported in the wild as of the publication date. The vulnerability primarily threatens confidentiality without affecting integrity or availability. The affected product is LibreOffice, a widely used open-source office suite, particularly popular in European public administrations and enterprises. The vulnerability was publicly disclosed on January 7, 2025, and no official patch links were provided in the source data, but upgrading to version 24.8.4 or later is recommended to remediate the issue.

For European organizations, this vulnerability poses a risk of sensitive information leakage, which can lead to exposure of confidential environmental variables and configuration data. Such data may include credentials, API keys, or internal network information, which could facilitate further attacks or unauthorized access. Organizations in regulated sectors such as finance, healthcare, and government are particularly vulnerable due to strict data protection requirements under GDPR and other regulations. The exploitation requires user interaction (opening a malicious document), so phishing or social engineering could be vectors. The impact is primarily on confidentiality, potentially undermining trust and compliance posture. While the vulnerability does not directly affect system integrity or availability, the leaked information could be leveraged in subsequent attacks, increasing overall risk. The widespread use of LibreOffice in European public sectors and enterprises increases the potential attack surface. Lack of known exploits in the wild reduces immediate risk but does not eliminate the threat, especially as attackers may develop exploits following disclosure.

1. Upgrade LibreOffice installations to version 24.8.4 or later as soon as possible to apply the fix addressing this vulnerability. 2. Implement strict document handling policies, including disabling automatic link expansion or external content loading in LibreOffice where feasible. 3. Educate users to avoid opening documents from untrusted or unknown sources, emphasizing the risk of crafted URLs within documents. 4. Employ network-level controls such as web proxies or firewalls to monitor and block suspicious outbound connections that could be used for data exfiltration. 5. Audit and restrict environment variables and INI file contents to minimize sensitive data exposure on endpoints running LibreOffice. 6. Use endpoint detection and response (EDR) tools to monitor for unusual network activity originating from user workstations. 7. Regularly review and update security policies related to document processing and user privileges to reduce attack surface. 8. Consider sandboxing or isolating document viewers to limit potential data leakage vectors.