EUVD-2026-16666
GHSA-89f7-r7x8-83q7
CVSS Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
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3Tags
Description
The '/api/v1/files/images/{flow_id}/{file_name}' endpoint serves SVG files with the 'image/svg+xml' content type without sanitizing their content. Since SVG files can contain embedded JavaScript, an attacker can upload a malicious SVG that executes arbitrary JavaScript when viewed by other users, leading to stored cross-site scripting (XSS). This allows stealing authentication tokens stored in cookies, including JWT access and refresh tokens.
Analysis
Stored cross-site scripting (XSS) in an unidentified web application's file serving endpoint allows authenticated attackers to steal session tokens including JWT access and refresh tokens by uploading malicious SVG files containing embedded JavaScript. The vulnerability affects the '/api/v1/files/images/{flow_id}/{file_name}' endpoint which serves SVG content without sanitization, enabling token theft when victims view the uploaded images. …
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Remediation
Within 24 hours: Identify the affected application vendor and confirm if your organization uses it; restrict file upload permissions to administrative users only. Within 7 days: Deploy WAF rules to block SVG files containing script tags on the vulnerable endpoint (/api/v1/files/images/{flow_id}/{file_name}) and implement Content-Security-Policy headers to prevent inline script execution. …
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