CVE-2021-39222: XSS in Talk

Severity: medium (CVSS 6.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-11-15 · updated 2026-06-17
Weakness: CWE-79

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.

Affected products

Nextcloud Talk: before 10.0.7; from 10.1.0 before 10.1.4; from 11.0.0 before 11.1.2 — fixed in 10.0.7, 10.1.4, 11.1.2

How to fix

Upgrade to a fixed version: Nextcloud Talk 10.0.7, 10.1.4, 11.1.2. Check the vendor advisory for mitigations.

References

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