# CVE-2026-52798: Gogs stored XSS in Jupyter notebook preview

Source: https://junglewise.ai/threats/cve-2026-52798-gogs-stored-xss-in-jupyter-notebook-preview  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-24. Updated: 2026-06-24  
License: CC BY 4.0 with a link back

CVE-2026-52798 · Severity: high · CVSS 8.9 · Published 2026-06-24

Gogs is an open-source self-hosted Git service used by developers to manage source code. A security flaw in how the platform previews Jupyter Notebook (.ipynb) files allows an attacker to embed malicious code within a file. If a user views a specially crafted notebook and clicks a link within it, the attacker can execute commands in the user's browser, potentially leading to account takeover, data theft, or unauthorized repository changes.

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 CVE-2026-52798 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-52798 being exploited in the wild.

**How severe is CVE-2026-52798?** High severity, with a CVSS score of 8.9, published 24 June 2026.

**Which products and versions are affected?** gogs.io/gogs (Go) <= 0.14.2, SEMVER:introduced=0, SEMVER:introduced=0,fixed=0.14.3; Gogs < 0.14.3, <= 0.14.2.

**Is there a fix for CVE-2026-52798?** Yes. gogs.io/gogs (Go): upgrade to 0.14.3 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-52798 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-52798?** 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.

## How to fix

- gogs.io/gogs (Go): upgrade to 0.14.3 or later

  ```sh
  go get gogs.io/gogs@v0.14.3
  ```


## Technical details

A Stored Cross-Site Scripting (XSS) vulnerability exists in Gogs' handling of Jupyter Notebook (.ipynb) previews. While the server-side sanitization via '/-/api/sanitize_ipynb' correctly filters initial input, the application subsequently re-renders Markdown cells on the client side using the 'marked()' library on elements with the '.nb-markdown-cell' class. This client-side re-rendering process fails to re-sanitize the content, allowing 'javascript:', 'vbscript:', or 'data:' URI schemes to be regenerated into clickable links. An attacker with repository write access can commit a malicious .ipynb file; when a victim views the file and clicks the link, arbitrary JavaScript executes within the Gogs origin. The issue was addressed in version 0.14.3 by upgrading 'marked.js' to version 4.3.0 and implementing a URL scheme blocklist.

## Affected products

- Gogs Gogs < 0.14.3

## Identifiers

- CVE-2026-52798
- GHSA-jq8v-rmf6-65jw
- GO-2026-5477

## Timeline

- 2026-06-04: patched: Fix merged into main branch
- 2026-06-07: advisory: Release 0.14.3 published
- 2026-06-24: disclosed: CVE-2026-52798 published to NVD

## References

- [https://github.com/gogs/gogs/commit/17b168b11ca759a7550e1f4bbd68bbde14db7785](https://github.com/gogs/gogs/commit/17b168b11ca759a7550e1f4bbd68bbde14db7785)
- [https://github.com/gogs/gogs/pull/8319](https://github.com/gogs/gogs/pull/8319)
- [https://github.com/gogs/gogs/releases/tag/v0.14.3](https://github.com/gogs/gogs/releases/tag/v0.14.3)
- [https://github.com/gogs/gogs/security/advisories/GHSA-jq8v-rmf6-65jw](https://github.com/gogs/gogs/security/advisories/GHSA-jq8v-rmf6-65jw)

## 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)