Medium 5.4Published Jun 24, 2026

CVE-2026-52816Gogs: Unauthenticated Jupyter Notebook (ipynb) Sanitizer allows arbitrary data: URIs leading to XSS

Updated under an hour ago (Oct 26, 2026, 5:00 AM ET)

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Exploited in the last 30 days

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.

CVSS: 5.4 MEDIUM (v4.0, CNA)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/E:P
Weakness (CWE): CWE-80
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Deferred
Record last updated: Jun 25, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

gogs gogs gogs:gogs (from the name)	before 0.14.3	CNA record

References

https://github.com/gogs/gogs/security/advisories/GHSA-3w28-36p9-w929x-refsource-confirm
https://github.com/gogs/gogs/pull/8326x-refsource-misc
https://github.com/gogs/gogs/commit/dd1bd9837aa196b3ed3a8ee21e5727b5d7a986a3x-refsource-misc
https://github.com/gogs/gogs/releases/tag/v0.14.3x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.