XSS in Nextcloud Contacts
CVE-2021-39221
Nextcloud is an open-source, self-hosted productivity platform. The Nextcloud Contacts application prior to version 4.0.3 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 Contacts application is upgraded to 4.0.3. As a workaround, one may use a browser that has support for Content-Security-Policy.
Vulnerability class: XSS (Cross-Site Scripting)
EPSS: 0.005 (40.2th percentile) — read the EPSS interpretation.
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.
Affected products
- Nextcloud Contacts
- Nextcloud Security-advisories — versions < 4.0.3
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Third Party Advisory)
- security-advisories@github.com (Third Party Advisory, x_refsource_MISC)
Frequently asked questions
- What is CVE-2021-39221?
- CVE-2021-39221 is a medium-severity vulnerability in Nextcloud Contacts, classified under Cross-site Scripting. CVSS score: 6.4/10. Published 2021-10-25.
- How severe is CVE-2021-39221?
- Medium severity. CVSS v3 base score is 6.4 out of 10.