CVE-2026-38446 in osTicket
Summary
by MITRE • 08/03/2026
A stored cross-site scripting (XSS) vulnerability exists in osTicket 1.18.3 due to improper sanitization of the thread entry title field. User-controlled input in the title is stored without adequate HTML escaping and later rendered in multiple staff-facing templates without proper output encoding. An attacker can inject arbitrary JavaScript by submitting a crafted ticket reply or email with a malicious subject line.
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Analysis
by VulDB Data Team • 08/03/2026
The stored cross-site scripting vulnerability in osTicket 1.18.3 represents a critical security flaw that undermines the integrity of the ticketing system's user interface and data handling mechanisms. This vulnerability resides within the thread entry title field where user input fails to undergo proper sanitization processes before being stored in the database. The flaw manifests when administrators or staff members view ticket entries, as the unescaped content gets rendered directly into web pages without appropriate output encoding, creating an environment ripe for malicious code execution.
The technical implementation of this vulnerability stems from inadequate input validation and output encoding practices within the application's core processing logic. When users submit ticket replies or email communications containing crafted subject lines, the system stores these inputs verbatim without performing HTML escaping operations that would neutralize potentially harmful script tags or other malicious payloads. This represents a classic CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability where the application fails to properly encode data before incorporating it into dynamically generated web content.
The operational impact of this vulnerability extends beyond simple data corruption or display issues, as it enables attackers to execute arbitrary JavaScript code within the context of authenticated users' browsers. When staff members view affected ticket entries containing malicious payloads, their browsers execute the injected scripts, potentially leading to session hijacking, credential theft, or unauthorized access to sensitive administrative functions. Attackers can leverage this vulnerability to escalate privileges, modify ticket contents, or gain persistent access to the system through compromised administrator sessions.
The exploitation of this vulnerability aligns with ATT&CK technique T1566.002 - Phishing: Spearphishing Attachment, as attackers can craft malicious email subject lines that appear legitimate while containing embedded JavaScript payloads. The attack vector requires minimal technical expertise and can be executed through standard email-based delivery mechanisms, making it particularly dangerous in enterprise environments where administrators frequently interact with ticketing systems. Security professionals should note that this vulnerability affects the staff-facing templates specifically, meaning the impact is most severe when authenticated users view affected content.
Mitigation strategies should include immediate implementation of proper HTML escaping for all user-controllable input fields prior to database storage, combined with output encoding during template rendering processes to prevent script execution. Organizations must also implement comprehensive input validation mechanisms that reject or sanitize potentially malicious content before it enters the system. The recommended approach aligns with OWASP Secure Coding Practices and involves establishing a robust sanitization framework that addresses both input and output handling within the application's data flow architecture. Regular security updates and patch management procedures should be implemented to ensure such vulnerabilities are promptly addressed without requiring extensive code modifications or architectural changes.