20th October 2020
Risk level: Low
CVSS v3 Base Score: 5.5 (AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:L)
CWE: Cross-site Scripting (XSS) - Stored (CWE-79)
HackerOne report: 998422
A missing file type check in Nextcloud Contacts 3.4.0 allowed a malicious user to upload SVG files as PNG files to perform XSS attacks.
The error has been fixed.
It is recommended that the Nextcloud Contacts is upgraded to 3.4.1.
The Nextcloud team thanks the following people for their research and responsible disclosure of the above advisory: