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XSS through image upload on contacts using svg file with png extension (NC-SA-2020-044)

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.

Affected Software

  • Nextcloud Contacts < 3.4.1 (CVE-2020-8280)

Action Taken

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:

  • Tommy Suriel - Vulnerability discovery and disclosure.

This advisory is licensed CC BY-SA 4.0.

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