CVE-2025-43558 is a high-severity out-of-bounds write vulnerability (CWE-787) affecting Adobe InDesign Desktop versions ID20.2, ID19.5.3, and earlier. This vulnerability arises when the software improperly handles memory boundaries, allowing an attacker to write data outside the intended buffer limits. Such memory corruption can lead to arbitrary code execution within the context of the current user. Exploitation requires user interaction, specifically the opening of a maliciously crafted InDesign file. Successful exploitation could allow an attacker to execute arbitrary code, potentially leading to full compromise of the user's environment with the privileges of the logged-in user. The CVSS v3.1 base score is 7.8, reflecting high impact on confidentiality, integrity, and availability, with low attack complexity but requiring user interaction and local vector (local access to open the file). There are no known exploits in the wild at the time of publication, and no patches have been linked yet. The vulnerability is significant because InDesign is widely used in professional publishing and creative industries, and malicious files could be distributed via email, shared drives, or compromised websites. The vulnerability's exploitation scope is limited to users who open malicious files, but the impact on affected systems can be severe, including data theft, system manipulation, or further malware deployment.

For European organizations, especially those in media, publishing, advertising, and creative sectors where Adobe InDesign is a critical tool, this vulnerability poses a substantial risk. Successful exploitation could lead to unauthorized access to sensitive intellectual property, client data, and internal documents. The arbitrary code execution capability could be leveraged to install ransomware, spyware, or other malware, disrupting business operations and causing financial and reputational damage. Given the high confidentiality and integrity impact, organizations handling regulated data (e.g., GDPR-protected personal data) could face compliance violations and penalties if breaches occur. The requirement for user interaction means phishing or social engineering campaigns could be used to trick employees into opening malicious files, increasing the risk in environments with less stringent security awareness. Additionally, the lack of a patch at the time of disclosure means organizations must rely on interim mitigations, increasing exposure duration. The impact extends beyond individual users to potentially compromise enterprise networks if lateral movement is achieved post-exploitation.

1. Implement strict email and file filtering to block or quarantine suspicious InDesign files, especially from unknown or untrusted sources. 2. Increase user awareness and training focused on recognizing phishing attempts and the risks of opening unsolicited or unexpected files. 3. Employ application whitelisting and sandboxing techniques to restrict InDesign's ability to execute arbitrary code or interact with critical system components. 4. Use endpoint detection and response (EDR) solutions to monitor for anomalous behavior indicative of exploitation attempts. 5. Enforce the principle of least privilege for user accounts to limit the impact of any successful code execution. 6. Regularly back up critical data and verify recovery procedures to mitigate ransomware risks. 7. Monitor Adobe's security advisories closely and apply patches immediately once available. 8. Consider disabling or restricting the use of InDesign on systems that do not require it or use alternative software where feasible until patches are released.