CVE-2021-45054 is a use-after-free vulnerability (CWE-416) identified in Adobe InCopy, specifically affecting version 16.4 and earlier. The vulnerability arises during the processing of JPEG2000 image files within the application. A use-after-free flaw occurs when a program continues to use a pointer after the memory it points to has been freed, potentially leading to undefined behavior including memory corruption or disclosure of sensitive information. In this case, exploitation could allow an attacker to disclose sensitive memory contents, which may include critical application or system data. Furthermore, the vulnerability could be leveraged to bypass security mitigations such as Address Space Layout Randomization (ASLR), which is designed to prevent exploitation of memory corruption bugs by randomizing memory addresses. However, exploitation requires user interaction, specifically that the victim opens a maliciously crafted JPEG2000 file in Adobe InCopy. There are no known exploits in the wild as of the published date, and no official patches have been linked in the provided information. The vulnerability is classified as medium severity by the vendor. The lack of a CVSS score necessitates an independent severity assessment based on the impact and exploitability factors.

For European organizations, the impact of this vulnerability could be significant in environments where Adobe InCopy is used, particularly in media, publishing, and creative industries that rely on Adobe's suite of products. Successful exploitation could lead to unauthorized disclosure of sensitive memory contents, potentially exposing confidential documents, credentials, or other sensitive data processed or cached by the application. The ability to bypass ASLR increases the risk of further exploitation, possibly enabling attackers to chain this vulnerability with others to achieve code execution or privilege escalation. However, since exploitation requires user interaction and opening a malicious file, the attack surface is somewhat limited to targeted phishing or social engineering campaigns. The absence of known exploits reduces immediate risk but does not eliminate the threat, especially as attackers may develop exploits over time. Organizations handling sensitive editorial content or intellectual property should be particularly vigilant. Additionally, the vulnerability could be leveraged in supply chain attacks where malicious files are distributed through trusted channels.

1. Immediate mitigation should include updating Adobe InCopy to the latest version once Adobe releases a patch addressing CVE-2021-45054. Until then, organizations should implement strict file handling policies, including disabling or restricting the opening of JPEG2000 files from untrusted or unknown sources within Adobe InCopy. 2. Employ email and endpoint security solutions capable of detecting and blocking malicious file attachments, particularly those containing JPEG2000 images. 3. Conduct user awareness training focused on the risks of opening unsolicited or suspicious files, emphasizing the specific threat vector involving JPEG2000 files in Adobe InCopy. 4. Implement application whitelisting and sandboxing techniques for Adobe InCopy to limit the potential impact of exploitation. 5. Monitor network and endpoint logs for unusual activity related to Adobe InCopy processes, especially after file opening events. 6. Consider disabling or limiting the use of Adobe InCopy in environments where it is not essential, or replace it with alternative software until the vulnerability is patched. 7. Maintain up-to-date backups and incident response plans to quickly recover from potential exploitation scenarios.