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TI-2021-18017 Aliases CVE-2021-41178

File Traversal affecting SVG files on Nextcloud Server

Priority MEDIUM 42CWE-23Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-434.

Summary

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.

Why it matters now

EPSS 0.01784 78th percentileScored 2026-11-07
Fix Fixed security-advisories (nextcloud): 21.0.5, 22.2.0

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
nextcloudsecurity-advisories20.0.13; 21.0.0 to before 21.0.5; before 22.2.021.0.5, 22.2.0Patch availableCNA
  • security-advisories Vendornextcloud Affected 20.0.13; 21.0.0 to before 21.0.5; before 22.2.0 Fixed in 21.0.5, 22.2.0 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:nextcloud:server:*:*:*:*:*:*:*:*20.0.3 to before 20.0.13; 21.0.1 to before 21.0.5; 22.1.1 to before 22.2.0Vulnerablenextcloud
  • cpe:2.3:a:nextcloud:server:*:*:*:*:*:*:*:* Versions 20.0.3 to before 20.0.13; 21.0.1 to before 21.0.5; 22.1.1 to before 22.2.0 Vulnerable ·nextcloud

Remediation

  • Fix · CNA security-advisories (nextcloud) Fixed in 21.0.5, 22.2.0

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-41178

References

Patch 1

Advisory 2

Other 1

  • TI-2021-18018 Two-Factor Authentication not enforced for pages marked as public CVSS 3.1MEDIUM 6.5

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences