CVE-2021-39222

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.

Weakness classification

• CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
• CWE-434: Unrestricted Upload of File with Dangerous Type

Primary references

• security-advisories@github.com — Third Party Advisory
• security-advisories@github.com — Third Party Advisory
• security-advisories@github.com — Permissions Required, Third Party Advisory
• af854a3a-2127-422b-91ae-364da2661108 — Third Party Advisory
• af854a3a-2127-422b-91ae-364da2661108 — Third Party Advisory
• af854a3a-2127-422b-91ae-364da2661108 — Permissions Required, Third Party Advisory