CVE-2026-121588 in TeXlyre
Summary
by MITRE • 11/03/2026
TeXlyre from 0.11.0 before 0.13.5 contains a stored cross-site scripting vulnerability that allows attackers to execute script by supplying malicious LSP or typesetter recipe icons. Attackers can trick victims into importing a recipe whose icon contains an HTML event handler, persistently accessing local projects and repository credentials.
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Analysis
by VulDB Data Team • 11/03/2026
The software TeXlyre, specifically versions ranging from 0.11.0 up to but not including 0.13.5, is susceptible to a stored cross-site scripting vulnerability that poses significant risks to user data integrity and confidentiality. This flaw arises because the application fails to adequately sanitize or validate input when processing LSP (Language Server Protocol) configurations or typesetter recipe icons provided by users. Unlike reflected XSS attacks where malicious scripts are executed immediately within a web session, this vulnerability is classified as stored because the injected payload is persistently saved on the server-side database associated with the user's project settings or repository configuration. Consequently, every time a victim loads their workspace or views the affected recipe list, the browser executes the embedded script automatically without requiring further interaction from the attacker beyond the initial injection phase.
The technical mechanism of this exploit relies on the application rendering icon data directly into HTML elements without proper encoding. By supplying an image URL that points to a malicious resource containing JavaScript code wrapped in event handlers such as onload or onclick, attackers can trigger execution within the context of the victim's authenticated session. Since TeXlyre is designed for LaTeX document preparation and often integrates with version control systems like Git, the application typically maintains persistent connections to remote repositories. This architectural design means that any script executed in this context inherits the full privileges of the logged-in user, including access tokens, API keys, and SSH credentials stored locally or passed during synchronization processes.
The operational impact of this vulnerability is severe due to its potential for data exfiltration and unauthorized system modification. Attackers can leverage the persistent nature of the script to silently harvest sensitive information such as local project files, source code repositories, and authentication tokens used to access private Git hosts like GitHub or GitLab. This capability allows adversaries to steal intellectual property, inject malicious code into legitimate projects, or use compromised credentials to pivot further into internal networks if those credentials have broader permissions. The persistence of the payload ensures that even after the initial attack vector is discovered, subsequent visits by other users who view the same project will also trigger the script, potentially leading to a widespread compromise across multiple user accounts sharing the affected repository.
From a classification perspective, this vulnerability aligns with CWE-79, which describes Improper Neutralization of Input During Web Page Generation commonly known as Cross-site Scripting. The specific behavior of storing malicious input in a database for later retrieval and execution also maps to CWE-83, Stored XSS. In terms of adversary tactics, the exploitation phase corresponds to MITRE ATT&CK technique T1059, Command and Scripting Interpreter, specifically through browser-based scripting environments like JavaScript. Furthermore, the theft of credentials aligns with T1556, Credential API Hijacking or T1539, Steal Web Session Cookie, depending on how the application handles session management during script execution.
Mitigation strategies for this vulnerability must focus on both immediate remediation and long-term defensive coding practices. The primary solution is to upgrade TeXlyre to version 0.13.5 or later where the input validation logic has been corrected to properly escape special characters in icon URLs before rendering them in HTML contexts. For organizations unable to immediately patch, implementing a Content Security Policy that restricts script execution from untrusted sources can provide an additional layer of defense by preventing inline scripts and unauthorized external resource loading. Additionally, developers should adopt strict output encoding standards such as OWASP ESAPI or utilize modern framework features that automatically handle context-aware escaping for HTML attributes and body content. Regular security audits focusing on how user-supplied data is processed in persistent storage mechanisms are essential to prevent similar stored injection flaws in future updates.