CVE-2026-9588 in Switchvox
Summary
by MITRE • 07/17/2026
A stored cross-site scripting (XSS) vulnerability exists in Sangoma Switchvox SMB Edition 8.3 (104997) within the voicemail notification template functionality. The submit_modify_voicemail_template endpoint fails to properly sanitize HTML content supplied by authenticated users, allowing malicious JavaScript supplied through the template_text parameter to be stored server-side and subsequently rendered to other users.
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Analysis
by VulDB Data Team • 07/17/2026
This vulnerability represents a critical stored cross-site scripting flaw in Sangoma Switchvox SMB Edition 8.3 that stems from inadequate input validation within the voicemail notification template system. The issue manifests through the submit_modify_voicemail_template endpoint which processes user-supplied content without proper sanitization measures, creating an environment where malicious actors can inject persistent JavaScript code into the application's server-side storage mechanisms. The vulnerability specifically affects the template_text parameter which accepts HTML content from authenticated users, allowing attackers to bypass security controls that should normally prevent execution of untrusted code within the application context.
The technical exploitation of this vulnerability follows a well-established XSS attack pattern where malicious code is first stored on the server and then executed when other users view the affected voicemail templates. This persistent nature differentiates it from reflected XSS attacks and makes it particularly dangerous as the malicious payload can affect multiple users over extended periods. The vulnerability directly maps to CWE-79 which defines the weakness of insufficient input sanitization leading to cross-site scripting vulnerabilities, and aligns with ATT&CK technique T1566.001 for initial access through malicious web content.
The operational impact of this vulnerability extends beyond simple data theft or session hijacking as it provides attackers with complete control over the affected application's user interface. An attacker who gains access to a valid account can craft malicious templates that execute arbitrary JavaScript code against other users, potentially leading to credential theft, privilege escalation, or full system compromise. The authenticated nature of the vulnerability means that attackers need only obtain legitimate user credentials rather than bypassing authentication entirely, making this attack vector particularly concerning for enterprise environments where such systems are commonly deployed.
Mitigation strategies should focus on implementing robust input sanitization mechanisms at multiple layers within the application architecture. The most effective immediate fix involves implementing comprehensive HTML sanitization libraries that strip or encode dangerous elements from user-supplied content before storage, ensuring that only safe markup remains in the database. Additionally, strict content security policies should be enforced to prevent execution of inline scripts even if sanitization fails. Organizations should also implement proper access controls and monitoring around template modification functions, as well as regular security assessments of web application components to identify similar vulnerabilities in other areas of the system. The vulnerability demonstrates the critical importance of defense-in-depth approaches that combine multiple security controls rather than relying on single points of failure within application logic.