CVE-2026-21272 is an improper input validation vulnerability (CWE-20) found in Adobe Dreamweaver Desktop versions 21.6 and earlier. This flaw allows an attacker to perform arbitrary file system writes by crafting malicious files that, when opened by a victim, exploit the vulnerability to inject or manipulate data on the victim's system. The vulnerability requires user interaction, specifically the victim opening a malicious file, but does not require any privileges or authentication. The CVSS v3.1 score is 8.6 (high), with vector AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H, indicating local attack vector, low attack complexity, no privileges required, user interaction required, scope changed, and high impact on confidentiality, integrity, and availability. The scope change means the vulnerability affects resources beyond the originally vulnerable component, increasing its severity. Although no known exploits are currently reported in the wild, the potential for significant damage exists due to the ability to write arbitrary files, which could lead to code execution, data corruption, or system compromise. No patches or mitigation updates have been published at the time of this report, highlighting the need for proactive defensive measures. The vulnerability primarily affects users of Adobe Dreamweaver Desktop, a widely used web development tool, which is prevalent in organizations managing web content and applications.

For European organizations, this vulnerability poses a substantial risk, especially those involved in web development, digital content creation, and IT infrastructure management using Adobe Dreamweaver Desktop. Successful exploitation can lead to unauthorized modification or injection of malicious files, potentially resulting in full system compromise, data breaches, or disruption of web services. The high impact on confidentiality, integrity, and availability means sensitive corporate data and customer information could be exposed or altered. Additionally, compromised systems could be leveraged as footholds for further lateral movement within networks. The requirement for user interaction limits mass exploitation but does not eliminate risk, as targeted phishing or social engineering campaigns could induce users to open malicious files. The absence of patches increases the window of exposure, necessitating immediate risk management. Organizations with regulatory obligations under GDPR must be particularly vigilant to prevent data breaches and ensure compliance.

1. Implement strict file handling policies restricting the types of files that can be opened with Dreamweaver Desktop, especially from untrusted sources. 2. Educate users on the risks of opening files from unknown or suspicious origins and promote cautious behavior regarding email attachments and downloads. 3. Employ endpoint protection solutions capable of detecting anomalous file system writes or modifications related to Dreamweaver processes. 4. Use application whitelisting and sandboxing to limit the ability of Dreamweaver to write to sensitive directories or execute unauthorized code. 5. Monitor system and application logs for unusual activity indicative of exploitation attempts. 6. Maintain up-to-date backups of critical data to enable recovery in case of compromise. 7. Coordinate with Adobe for timely patch deployment once available and test patches in controlled environments before widespread rollout. 8. Consider network segmentation to isolate development environments from critical production systems to limit potential lateral movement.