XSS in Nextcloud Security-Advisories
CVE-2021-39222
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.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.4 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N.
EPSS exploit prediction
EPSS: 0.011 (64.3th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 64th percentile — 64.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.011 · newest: 0.011 · change: +0.000
Affected products
- Nextcloud Security-Advisories — versions < 10.0.7, >= 10.1.0, < 10.1.4, >= 11.1.0, < 11.1.2
- Nextcloud Talk
Weakness classification (CWE)
References
- github.com/nextcloud/security-advisories/security/advisories/GHSA-xhxq-f4vg-jw5g (Third Party Advisory)
- github.com/nextcloud/spreed/pull/542 (Third Party Advisory)
- hackerone.com/reports/1135481 (Permissions Required, Third Party Advisory)
Frequently asked questions
- What is CVE-2021-39222?
- CVE-2021-39222 is a medium-severity vulnerability in Nextcloud Security-Advisories, classified under Cross-site Scripting. CVSS score: 6.4/10. Published 2021-11-15.
- How severe is CVE-2021-39222?
- Medium severity. CVSS v3 base score is 6.4 out of 10.