CVE-2021-39222 - CVE House
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Status published Medium CVE-2021-39222

XSS in Talk

Vulnerability 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.

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

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Credits & Attribution

No credits recorded in the NVD database.

References

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Affected Vendor

Affected Software

security-advisories
Vulnerable Versions:
< 10.0.7, >= 10.1.0, < 10.1.4, >= 11.1.0, < 11.1.2, < 11.2.0, >= 12.0.0.alpha-1, < 12.0.0

Timeline

Official Publish: November 15th, 2021
Last Modified: August 4th, 2024
Added to House: July 21st, 2026

CVSS Vectors

V3: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N

Weaknesses (CWE)

CWE-434 CWE-79

MITRE ATT&CK TTPs

T1190 Exploit Public-Facing Application
Initial Access
T1505.003 Web Shell
Persistence
T1105 Ingress Tool Transfer
Command and Control
T1059 Command and Scripting Interpreter
Execution
T1565.002 Stored Data Manipulation
Impact
T1189 Drive-by Compromise
Initial Access
T1059.007 JavaScript
Execution
T1539 Steal Web Session Cookie
Collection
T1213 Data from Information Repositories
Collection
T1567 Exfiltration Over Web Service
Exfiltration
T1491.001 Defacement
Impact