CVE-2026-21275 is a vulnerability classified under CWE-824 (Access of Uninitialized Pointer) affecting Adobe InDesign Desktop versions 21.0, 19.5.5, and earlier. The flaw arises when the software accesses memory pointers that have not been properly initialized, potentially allowing an attacker to manipulate program execution flow. By crafting a malicious InDesign file and convincing a user to open it, an attacker can trigger arbitrary code execution with the privileges of the current user. This type of vulnerability is critical because it can lead to full compromise of the user's environment, including data theft, installation of malware, or further lateral movement within a network. The CVSS 3.1 vector (AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H) indicates that the attack requires local access (local vector), low attack complexity, no privileges, but user interaction is necessary. The scope is unchanged, meaning the impact is limited to the vulnerable component and user context. Although no exploits are known in the wild yet, the vulnerability's nature and severity make it a prime candidate for exploitation once weaponized. The absence of available patches at the time of publication increases the urgency for mitigation through alternative controls.

The vulnerability allows attackers to execute arbitrary code with the current user's privileges, potentially leading to data theft, unauthorized system modifications, or deployment of persistent malware. Since Adobe InDesign is widely used in creative industries, marketing, publishing, and media production, exploitation could disrupt critical business workflows and compromise sensitive intellectual property. The requirement for user interaction (opening a malicious file) means social engineering or phishing campaigns could be used to deliver the exploit. Organizations with many users handling InDesign files are at risk of widespread impact if targeted. The vulnerability affects confidentiality, integrity, and availability, as attackers can access sensitive data, alter files or system settings, and cause application or system crashes. The lack of patches increases exposure time, and the high CVSS score reflects the significant risk posed by this flaw.

Until official patches are released, organizations should implement strict controls on the handling of InDesign files from untrusted sources, including disabling automatic opening of files and educating users about the risks of opening suspicious documents. Employ endpoint protection solutions capable of detecting anomalous behaviors related to InDesign processes. Use application whitelisting to restrict execution of unauthorized code. Network segmentation can limit lateral movement if a compromise occurs. Monitor logs for unusual activity associated with InDesign usage. Regularly update Adobe InDesign to the latest versions once patches become available. Consider sandboxing or running InDesign in isolated environments for high-risk users. Additionally, implement strong email filtering and phishing awareness training to reduce the likelihood of malicious file delivery.