Gogs is an open source self-hosted Git service. Prior to 0.14.3, the Jupyter Notebook (ipynb) sanitizer endpoint at POST /-/api/sanitize_ipynb allows arbitrary data: URIs without proper restrictions, potentially leading to Cross-Site Scripting (XSS). The endpoint uses bluemonday.UGCPolicy() with p.AllowURLSchemes("data") which permits all data URI schemes including data:text/html, enabling attackers to inject malicious HTML/JavaScript. Additionally, the endpoint has no authentication middleware, allowing any registered user to exploit this vulnerability. This vulnerability is fixed in 0.14.3.
https://github.com/gogs/gogs/security/advisories/GHSA-3w28-36p9-w929
https://github.com/gogs/gogs/releases/tag/v0.14.3
https://github.com/gogs/gogs/pull/8326
https://github.com/gogs/gogs/commit/dd1bd9837aa196b3ed3a8ee21e5727b5d7a986a3
Published: 2026-06-24
Updated: 2026-06-25
Base Score: 4.3
Vector: CVSS2#AV:N/AC:M/Au:N/C:N/I:P/A:N
Severity: Medium
Base Score: 5.4
Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Severity: Medium
Base Score: 6.4
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N
Severity: Medium
EPSS: 0.00677