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TI-2021-16606 Aliases CVE-2021-39221

XSS in Contacts

Priority LOW 29CWE-434Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
Required
Attack complexity
High
Impact type
Code execution, Cross-site scripting
Confidentiality · integrity · availability
High · High · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-434 and CWE-79.

Summary

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.

Why it matters now

EPSS 0.00521 44th percentileScored 2026-11-07
Fix Fixed security-advisories (nextcloud): 4.0.3

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
nextcloudsecurity-advisoriesbefore 4.0.34.0.3Patch availableCNA
  • security-advisories Vendornextcloud Affected before 4.0.3 Fixed in 4.0.3 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:nextcloud:contacts:*:*:*:*:*:*:*:*before 4.0.3Vulnerablenextcloud
  • cpe:2.3:a:nextcloud:contacts:*:*:*:*:*:*:*:* Versions before 4.0.3 Vulnerable ·nextcloud

Remediation

  • Fix · CNA security-advisories (nextcloud) Fixed in 4.0.3

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-39221

References

Advisory 2

  • TI-2020-06698 Cross-site scripting in Nextcloud Contacts CVSS 3.1MEDIUM 5.4
  • TI-2020-06697 Cross-site scripting in Nextcloud Contacts CVSS 3.1MEDIUM 5.4
  • TI-2025-40965 Nextcloud Contacts vulnerable to Stored XSS in contacts app via organisation and title field CVSS 3.1MEDIUM 5.4
  • TI-2018-02760 Cross-site scripting in Nextcloud Contacts application CVSS 3.1MEDIUM 4.8
  • TI-2023-16359 Nextcloud Contacts photos only sanitized if mime type is all lower case CVSS 3.1MEDIUM 4.3
  • TI-2020-06599 A missing file type check in Nextcloud Contacts 3.2.0 allowed a malicious user to upload any file as avatars. CVSS 3.1MEDIUM 4.3

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences