Vulnerability · Published Oct 25, 2021 · Assigned by GitHub_M
CVE-2021-41178File Traversal affecting SVG files on Nextcloud Server
High 8.8
In plain English
A high-severity unrestricted file upload in security-advisories from nextcloud. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.8% (higher than 78% of all known vulnerabilities).
Official description
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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| nextcloud | security-advisories | 20.0.13>= 21.0.0, < 21.0.5< 22.2.0 |
Weakness: CWE-23, CWE-434 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
References
- https://github.com/nextcloud/security-advisories/security/advisories/GHSA-jp9c-vpr3-m5rf x_refsource_CONFIRM
- https://github.com/nextcloud/server/pull/28726 x_refsource_MISC
- https://hackerone.com/reports/1302155 x_refsource_MISC
- GLSA-202208-17 vendor-advisory, x_refsource_GENTOO