EUVD-2025-33193
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
Lifecycle Timeline
3Tags
Description
KUNO CMS is a fully deployable full-stack blog application. Versions 1.3.13 and below contain validation flaws in its file upload functionality that can be exploited for stored XSS. The upload endpoint only validates file types based on Content-Type headers, lacks file content analysis and extension whitelist restrictions, allowing attackers to upload SVG files containing malicious scripts (disguised as images). When users access the uploaded resource pages, arbitrary JavaScript executes in their browsers. This issue is fixed in version 1.3.14.
Analysis
KUNO CMS is a fully deployable full-stack blog application. Versions 1.3.13 and below contain validation flaws in its file upload functionality that can be exploited for stored XSS. The upload endpoint only validates file types based on Content-Type headers, lacks file content analysis and extension whitelist restrictions, allowing attackers to upload SVG files containing malicious scripts (disguised as images). When users access the uploaded resource pages, arbitrary JavaScript executes in their browsers. This issue is fixed in version 1.3.14.
Technical Context
Cross-site scripting (XSS) allows injection of client-side scripts into web pages viewed by other users due to insufficient output encoding.
Remediation
Encode all user-supplied output contextually (HTML, JS, URL). Implement Content Security Policy (CSP) headers. Use HTTPOnly and Secure cookie flags.
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External POC / Exploit Code
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