CVE-2021-45056 is an out-of-bounds write vulnerability (CWE-787) identified in Adobe InCopy, specifically affecting version 16.4 and earlier. This vulnerability arises when the software improperly handles memory boundaries during processing of certain input data, leading to the possibility of writing data outside the allocated buffer. Such an out-of-bounds write can corrupt memory, potentially allowing an attacker to execute arbitrary code within the security context of the current user. Exploitation requires user interaction, specifically the victim opening a maliciously crafted InCopy file. There are no known exploits in the wild as of the published date, and no official patches have been linked or released at the time of this analysis. The vulnerability is categorized as medium severity by the vendor, reflecting the requirement for user interaction and the absence of privilege escalation or automatic exploitation vectors. The attack vector is local or remote via social engineering, where an attacker convinces a user to open a malicious file, triggering the vulnerability. Successful exploitation could lead to execution of arbitrary code, potentially compromising the confidentiality, integrity, and availability of the affected system within the permissions of the user running InCopy. Given that Adobe InCopy is a professional desktop publishing software primarily used by editorial and publishing professionals, the vulnerability could be leveraged to target media organizations or creative agencies.

For European organizations, the impact of CVE-2021-45056 depends largely on the prevalence of Adobe InCopy usage within their workflows. Organizations in the publishing, media, advertising, and creative sectors that rely on Adobe InCopy for content creation and editorial processes are at risk. Exploitation could lead to unauthorized code execution, enabling attackers to deploy malware, steal sensitive editorial content, or disrupt publishing operations. This could result in intellectual property theft, reputational damage, and operational downtime. Since the vulnerability requires user interaction, phishing or spear-phishing campaigns targeting employees who handle InCopy files could be an effective attack vector. The impact is mitigated somewhat by the lack of privilege escalation; however, if the compromised user has elevated privileges or access to sensitive networks, the consequences could be more severe. Additionally, the absence of known exploits in the wild reduces immediate risk but does not eliminate the potential for future exploitation. European organizations with stringent data protection regulations (e.g., GDPR) may face compliance risks if a breach occurs due to this vulnerability.

1. Immediate mitigation should focus on user awareness and training to recognize and avoid opening suspicious or unsolicited InCopy files, especially those received via email or external sources. 2. Implement strict email filtering and attachment scanning to detect potentially malicious InCopy files before they reach end users. 3. Employ application whitelisting and sandboxing techniques to restrict the execution environment of Adobe InCopy, limiting the impact of any potential code execution. 4. Monitor and restrict user privileges where possible, ensuring that users running InCopy do not have unnecessary administrative rights. 5. Maintain up-to-date backups of critical editorial and publishing data to enable recovery in case of compromise. 6. Regularly check Adobe’s security advisories for patches or updates addressing this vulnerability and apply them promptly once available. 7. Use endpoint detection and response (EDR) tools to identify anomalous behavior indicative of exploitation attempts. 8. Network segmentation can limit lateral movement if a system is compromised. These measures go beyond generic advice by focusing on the specific attack vector (malicious file opening) and the operational context of Adobe InCopy usage.