CVE-2026-1592 is a stored cross-site scripting vulnerability identified in Foxit Software Inc.'s PDF Editor Cloud service hosted at pdfonline.foxit.com. The flaw exists in the Create New Layer feature, where user-supplied input is not properly sanitized before being embedded into the HTML output. This improper neutralization of input (CWE-79) allows an attacker with authenticated access to inject arbitrary JavaScript code that executes when the crafted layer is viewed by users. The vulnerability affects all versions of the service before the patch date of 2026-02-01. The CVSS 3.1 base score is 6.3, indicating a medium severity level, with the vector reflecting network attack vector (AV:N), low attack complexity (AC:L), requiring privileges (PR:L), user interaction (UI:R), unchanged scope (S:U), high confidentiality impact (C:H), low integrity impact (I:L), and no availability impact (A:N). Although no exploits have been reported in the wild, the vulnerability poses a significant risk of data exposure or session hijacking through malicious script execution. The flaw is particularly concerning in environments where multiple users collaborate on PDF documents via the cloud service, as it could be leveraged to steal sensitive information or perform actions on behalf of users. The vulnerability highlights the importance of robust input validation and output encoding in web applications, especially those handling complex document workflows.

For European organizations, this vulnerability could lead to unauthorized disclosure of sensitive information, including confidential document contents or user credentials, due to the high confidentiality impact. Attackers exploiting this XSS flaw could execute scripts in the context of other users, potentially leading to session hijacking, phishing, or lateral movement within the organization's cloud environment. Although the integrity and availability impacts are low or none, the breach of confidentiality can have severe consequences, especially for industries handling regulated data such as finance, healthcare, and government. The need for user interaction and authentication limits the attack surface but does not eliminate risk, particularly in large organizations with many users and complex workflows. Additionally, the use of cloud-based PDF editing tools is common in European enterprises, increasing exposure. Regulatory frameworks like GDPR impose strict requirements on protecting personal data, and exploitation of this vulnerability could result in compliance violations and reputational damage.

Organizations should prioritize updating to the patched version of Foxit PDF Editor Cloud as soon as it becomes available. Until then, restrict access to the Create New Layer feature to trusted users only and monitor usage for anomalous behavior. Implement strict Content Security Policies (CSP) to limit the execution of unauthorized scripts within the application context. Employ web application firewalls (WAFs) with rules tuned to detect and block XSS payloads targeting this service. Conduct regular security training to raise awareness about phishing and social engineering attacks that could leverage this vulnerability. Review and enhance input validation and output encoding practices in any custom integrations with Foxit services. Additionally, audit user privileges to minimize the number of users with rights to create layers, reducing the potential attack surface. Finally, monitor logs and network traffic for signs of exploitation attempts or unusual activity related to the PDF Editor Cloud platform.