Gogs: XSS in .ipynb files renderer due to outdated notebookjs

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

8.5 · CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N · score source

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Summary Gogs renders Jupyter notebook files (.ipynb) using jsvine/notebookjs, but the version is outdated, missing patches for known XSS vulnerabilities.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: <img width="1054" height="208" alt="image" src="https://github.com/user-attachments/assets/49b7f33c-c4df-4537-99e9-b1ea74f2c6de" / 3. 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" /…

Published by the source

19 Jun 2026, 21:42 UTC

Last modified by the source

13 Aug 2026, 13:44 UTC

Source last checked

26 Oct 2026, 15:28 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-6vxv-wg6j-5qwp

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# Patch Next advisory brief: GHSA-6vxv-wg6j-5qwp

Advisory: Gogs: XSS in .ipynb files renderer due to outdated notebookjs
IDs: GHSA-6vxv-wg6j-5qwp
Record: https://patchnext.com/advisories/ghsa-6vxv-wg6j-5qwp (revision 1, source checked 26 Oct 2026, 15:28 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: gogs.io/gogs 0.14.3. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go gogs.io/gogs: affected < 0.14.3; fixed in 0.14.3

## Suggested inspection (read-only)
- Go gogs.io/gogs: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on gogs.io/gogs.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-6vxv-wg6j-5qwp (GitHub-reviewed advisory GHSA-6vxv-wg6j-5qwp lists affected ranges: Go gogs.io/gogs >=0 <0.14.3)

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