CVE-2021-39222: nextcloud security-advisories Cross-site Scripting

Vulnerability summary

CVE-2021-39222 is a medium (CVSS 6.4) Cross-site Scripting vulnerability in nextcloud security-advisories. EPSS estimates a 1.10% chance of exploitation in the next 30 days, higher than 65.1% of scored vulnerabilities.

Timeline

1. 15-11-2021
   PublishedVulnerability first disclosed.
2. 04-08-2024
   Last modifiedVulnerability information updated.

Description

Nextcloud is an open-source, self-hosted productivity platform. The Nextcloud Talk application was vulnerable to a stored Cross-Site Scripting (XSS) vulnerability. For exploitation, a user would need to right-click on a malicious file and open the file in a new tab. Due the strict Content-Security-Policy shipped with Nextcloud, this issue is not exploitable on modern browsers supporting Content-Security-Policy. It is recommended that the Nextcloud Talk application is upgraded to patched versions 10.0.7, 10.1.4, 11.1.2, 11.2.0 or 12.0.0. As a workaround, use a browser that has support for Content-Security-Policy.

• CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
• CWE-434Unrestricted Upload of File with Dangerous TypeThe product allows the upload or transfer of dangerous file types that are automatically processed within its environment.