What’s Vulnerable › Vulnerabilities

CVE-2021-41178: File Traversal affecting SVG files on Nextcloud Server

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.8% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-10-25 · updated 2026-06-17
• Weakness: CWE-23

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

• Nextcloud Server: from 20.0.3 before 20.0.13; from 21.0.1 before 21.0.5; from 22.1.1 before 22.2.0 — fixed in 20.0.13, 21.0.5, 22.2.0

How to fix

Upgrade to a fixed version: Nextcloud Server 20.0.13, 21.0.5, 22.2.0. Check the vendor advisory for mitigations.

References

• https://github.com/nextcloud/security-advisories/security/advisories/GHSA-jp9c-vpr3-m5rf
• https://github.com/nextcloud/server/pull/28726
• https://hackerone.com/reports/1302155
• https://security.gentoo.org/glsa/202208-17
• https://github.com/nextcloud/security-advisories/security/advisories/GHSA-jp9c-vpr3-m5rf
• https://github.com/nextcloud/server/pull/28726
• https://hackerone.com/reports/1302155
• https://security.gentoo.org/glsa/202208-17

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