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)
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: 0.005 (41.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 42nd percentile — 41.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000
Affected products
- Nextcloud Contacts
- Nextcloud Security-Advisories — versions < 4.0.3
Weakness classification (CWE)
References
- github.com/nextcloud/security-advisories/security/advisories/GHSA-j6cx-mxqf-f9vc (Third Party Advisory)
- github.com/nextcloud/contacts/pull/2407 (Third Party Advisory)
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.