Nextcloud is an open-source, self-hosted productivity platform. Prior to versions 20.0.13, 21.0.5, and 22.2.0, a file traversal vulnerability makes an attacker able to download arbitrary SVG images from the host system, including user provided files. This could also be leveraged into a XSS/phishing attack, an attacker could upload a malicious SVG file that mimics the Nextcloud login form and send a specially crafted link to victims. The XSS risk here is mitigated due to the fact that Nextcloud employs a strict Content-Security-Policy disallowing execution of arbitrary JavaScript. It is recommended that the Nextcloud Server be upgraded to 20.0.13, 21.0.5 or 22.2.0. There are no known workarounds aside from upgrading.
Exploitability
AV:NAC:LPR:LUI:NScope
S:UImpact
C:HI:HA:H8.8/CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HInput Validation
Other