Medium severity · published Jun 24, 2026
CVE-2026-52816
Gogs: Unauthenticated Jupyter Notebook (ipynb) Sanitizer allows arbitrary data: URIs leading to XSS
5.4
CVSS
0.7%
EPSS
No
On KEV
Description
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.
Exploitation
Is it being used?
Exploit prediction (EPSS)0.7% · higher than 52% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
GO
gogs · gogs
< 0.14.3 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-52816
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-52816
github.com
https://github.com/gogs/gogs/commit/dd1bd9837aa196b3ed3a8ee21e5727b5d7a986a3
github.com
https://github.com/gogs/gogs/pull/8326
github.com
https://github.com/gogs/gogs/releases/tag/v0.14.3
github.com
https://github.com/gogs/gogs/security/advisories/GHSA-3w28-36p9-w929
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