CVE-2025-30342
MEDIUMCVSS Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Lifecycle Timeline
3Tags
Description
An XSS issue was discovered in OpenSlides before 4.2.5. When submitting descriptions such as Moderator Notes or Agenda Topics, an editor is shown that allows one to format the submitted text. This allows insertion of various HTML elements. When trying to insert a SCRIPT element, it is properly encoded when reflected; however, adding attributes to links is possible, which allows the injection of JavaScript via the onmouseover attribute and others. When a user moves the mouse over such a prepared link, JavaScript is executed in that user's session.
Analysis
An XSS issue was discovered in OpenSlides before 4.2.5. Rated medium severity (CVSS 5.4), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
Technical Context
This vulnerability is classified as Cross-Site Scripting (XSS) (CWE-79), which allows attackers to inject malicious scripts into web pages viewed by other users. An XSS issue was discovered in OpenSlides before 4.2.5. When submitting descriptions such as Moderator Notes or Agenda Topics, an editor is shown that allows one to format the submitted text. This allows insertion of various HTML elements. When trying to insert a SCRIPT element, it is properly encoded when reflected; however, adding attributes to links is possible, which allows the injection of JavaScript via the onmouseover attribute and others. When a user moves the mouse over such a prepared link, JavaScript is executed in that user's session. Affected products include: Openslides. Version information: before 4.2.5..
Affected Products
Openslides.
Remediation
No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Sanitize all user input, use Content-Security-Policy headers, encode output contextually (HTML, JS, URL). Use frameworks with built-in XSS protection.
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External POC / Exploit Code
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