CVE-2025-21133 is an integer underflow vulnerability (CWE-191) identified in Adobe Illustrator on iPad, specifically affecting versions 3.0.7 and earlier. The vulnerability occurs when the application improperly processes integer values, leading to an underflow condition where numeric values wrap around unexpectedly. This flaw can be exploited by an attacker who crafts a malicious Illustrator file that, when opened by a victim on the iPad, triggers the underflow and enables arbitrary code execution within the context of the current user. The attack vector requires user interaction, as the victim must open the malicious file, but no prior authentication or elevated privileges are necessary. The CVSS v3.1 base score of 7.8 reflects a high severity, with attack vector local (AV:L), low attack complexity (AC:L), no privileges required (PR:N), user interaction required (UI:R), unchanged scope (S:U), and high impact on confidentiality (C:H), integrity (I:H), and availability (A:H). Although no exploits are currently known in the wild, the vulnerability poses a significant risk to users of Illustrator on iPad, particularly in environments where untrusted files may be received or shared. The lack of available patches at the time of publication necessitates immediate mitigation strategies to reduce exposure.

The vulnerability allows attackers to execute arbitrary code with the privileges of the current user, potentially leading to full compromise of the affected device's user environment. This can result in unauthorized access to sensitive design files, intellectual property theft, data corruption, or denial of service by crashing the application or device. Since Illustrator is widely used in creative industries, exploitation could disrupt business operations, cause financial losses, and damage reputations. The requirement for user interaction limits mass exploitation but targeted attacks against designers, agencies, or enterprises using Illustrator on iPad remain a significant concern. The impact extends to confidentiality, integrity, and availability, making this a critical risk for organizations relying on this software for professional workflows.

Organizations and users should immediately restrict the opening of Illustrator files from untrusted or unknown sources on iPad devices. Implement strict file validation and scanning policies before opening files in Illustrator. Educate users about the risks of opening unsolicited or suspicious files, emphasizing the need for caution with email attachments and downloads. Monitor for updates from Adobe and apply patches promptly once available. Consider deploying mobile device management (MDM) solutions to enforce application restrictions and control file access. As a temporary measure, users may disable or limit Illustrator usage on iPads until a fix is released. Additionally, maintaining regular backups of critical design files can mitigate data loss in case of exploitation.