CVE-2021-39221
lowpriority · track · 22EPSS 0.005 · 44 %ileEUUSEPSS · scored 2026-10-28
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.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · low–medium · 3.5–6.4
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (2)
Products and version ranges known to be affected.
also known as (2)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (8)
External citations — patches, advisories, analysis.
- https://github.com/nextcloud/contacts/pull/2407cnnvd
- https://github.com/nextcloud/security-advisories/security/advisories/GHSA-j6cx-mxqf-f9vccnnvd
- https://nvd.nist.gov/vuln/detail/CVE-2021-39221cnnvd
- https://www.cybersecurity-help.cz/vdb/SB2021102612cnnvd
- https://github.com/nextcloud/contacts/pull/2407enisa_euvd
- https://github.com/nextcloud/security-advisories/security/advisories/GHSA-j6cx-mxqf-f9vcenisa_euvd
- https://github.com/nextcloud/contacts/pull/2407Third Party Advisorynvd
- https://github.com/nextcloud/security-advisories/security/advisories/GHSA-j6cx-mxqf-f9vcThird Party Advisorynvd
Attackers weaponise vulnerabilities like this against internet-exposed services. See what is exposed on your perimeter with a free passive scan.
Free scan