# Gogs XSS in Jupyter notebook renderer via outdated notebookjs

Source: https://junglewise.ai/threats/gogs-xss-in-jupyter-notebook-renderer-via-outdated-notebookjs-07feca4b  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-19. Updated: 2026-06-19  
License: CC BY 4.0 with a link back

Severity: high · CVSS 8.5 · Published 2026-06-19

Gogs, a self-hosted Git service, is vulnerable to a security flaw where malicious Jupyter notebook files can execute unauthorized code in a user's browser. An attacker with repository access can upload a specially crafted file that, when viewed by another user or administrator, could lead to account takeover. This occurs because the software uses an outdated component to display these notebook files.

Technologies: [gogs.io/gogs (Go)](https://junglewise.ai/threats/technologies/gogs-io-gogs), [Gogs](https://junglewise.ai/threats/technologies/gogs). Vendors: [Go](https://junglewise.ai/threats/vendors/go), [Gogs](https://junglewise.ai/threats/vendors/gogs).

## Quick answers

**Is This vulnerability exploited in the wild?** No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.

**How severe is This vulnerability?** High severity, with a CVSS score of 8.5, published 19 June 2026.

**Which products and versions are affected?** gogs.io/gogs (Go) < 0.14.3; Gogs < 0.14.3.

**Is there a fix for This vulnerability?** A patch was published on 2026-06-19: Fixed in version 0.14.3 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is This vulnerability attacked?** It is attacked over the network, in a hosted service.

**Am I affected?** Check whether you run gogs.io/gogs (Go) or Gogs at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

Gogs utilizes an outdated version of the notebookjs library (v0.4.2) to render Jupyter notebook (.ipynb) files. This version lacks patches for several known Cross-Site Scripting (XSS) vulnerabilities, specifically allowing the execution of arbitrary JavaScript through malicious HTML tags embedded in Markdown cells. An attacker with low privileges (the ability to create or contribute to a repository) can upload a crafted .ipynb file. When a victim views this file, the payload executes in the context of the victim's session, potentially allowing for session hijacking or account takeover. The issue is resolved in Gogs version 0.14.3 by updating the underlying dependency.

## Affected products

- Gogs Gogs < 0.14.3

## Timeline

- 2026-06-19: disclosed
- 2026-06-19: advisory
- 2026-06-19: patched: Fixed in version 0.14.3

## References

- [https://api.github.com/users/Aikido-Security](https://api.github.com/users/Aikido-Security)
- [https://github.com/Aikido-Security](https://github.com/Aikido-Security)
- [https://api.github.com/users/Aikido-Security/gists%7B/gist_id%7D](https://api.github.com/users/Aikido-Security/gists%7B/gist_id%7D)
- [https://api.github.com/users/Aikido-Security/repos](https://api.github.com/users/Aikido-Security/repos)
- [https://avatars.githubusercontent.com/u/240550485?v=4](https://avatars.githubusercontent.com/u/240550485?v=4)
- [https://api.github.com/users/Aikido-Security/events%7B/privacy%7D](https://api.github.com/users/Aikido-Security/events%7B/privacy%7D)

## Related threats

- [Gogs Git Smart HTTP authorization bypass](https://junglewise.ai/threats/cve-2026-123012-in-gogs-0-14-3-the-git-smart-http-authorization-layer-in)
- [Gogs open redirect via backslash normalization mismatch](https://junglewise.ai/threats/cve-2026-82402-gogs-is-an-open-source-self-hosted-git-service-prior-to-0-15-0)
- [GO-2026-5193 - Gogs: XSS in .ipynb files renderer due to outdated notebookjs in gogs.io/gogs](https://junglewise.ai/threats/go-2026-5193-gogs-xss-in-ipynb-files-renderer-due-to-outdated-d1e8727f)
- [Gogs stored XSS in Jupyter Notebook sanitizer endpoint](https://junglewise.ai/threats/cve-2026-52816-gogs-stored-xss-in-jupyter-notebook-sanitizer-endpoint)
- [Gogs unauthenticated information disclosure in organization teams API](https://junglewise.ai/threats/cve-2026-52815-gogs-unauthenticated-information-disclosure-in-organization-teams)