Vulnerability Database

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Total vulnerabilities in the database

Gogs: XSS in .ipynb files renderer due to outdated notebookjs — gogs.io/gogs

Summary

Gogs renders Jupyter notebook files (.ipynb) using jsvine/notebookjs, but the version is outdated, missing patches for known XSS vulnerabilities.

Details

Gogs uses version 0.4.2 of notebookjs to render Jupyter notebook files:

https://github.com/gogs/gogs/blob/7297aee50d4c115836c7de8a3a233daaef87b911/templates/base/head.tmpl#L47

The latest version of jsvine/notebookjs is 0.8.3, patching many XSS vulnerabilities in its releases. The proof of concept below shows an example working payload that renders HTML through Markdown.

PoC

  1. Create a new repository
  2. Create a file inside the repository named xss.ipynb and give it the following content:
{"cells": [{"cell_type": "markdown", "metadata": {}, "source": ["<img src=x onerror=\"alert(origin)\">"]}], "metadata": {}, "nbformat": 4, "nbformat_minor": 2}

<img width="1054" height="208" alt="image" src="https://github.com/user-attachments/assets/49b7f33c-c4df-4537-99e9-b1ea74f2c6de" />

  1. Save the file and view the file in Gogs. Notice that the XSS popup triggers:

<img width="1317" height="407" alt="image" src="https://github.com/user-attachments/assets/3b18d870-7194-41b0-92db-687e952abc07" />

Impact

Any user with rights to create repositories can create XSS payloads that take over the victim's account when visited. Either through their own exploration of the files or by directly linking them the vulnerable URL.

  • Published: Jun 19, 2026
  • Updated: Jun 20, 2026
  • GHSA: GHSA-6vxv-wg6j-5qwp
  • Severity: High
  • Exploit:
  • CISA KEV:

No technical information available.

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CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

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Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

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