What is CVE-2020-8280?

CVE-2020-8280 is a medium-severity vulnerability in Nextcloud Contacts, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2021-01-06.

How severe is CVE-2020-8280?

Medium severity. CVSS v3 base score is 5.4 out of 10.

XSS in Nextcloud Contacts

CVE-2020-8280

A missing file type check in Nextcloud Contacts 3.4.0 allows a malicious user to upload SVG files as PNG files to perform cross-site scripting (XSS) attacks.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2021-01-06 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.006 (48.3th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 48th percentile — 48.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000

Affected products

Nextcloud Contacts
Nextcloud Contacts — versions Fixed in 3.4.1

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

hackerone.com/reports/998422 (Exploit, Third Party Advisory)
nextcloud.com/security/advisory/ (Vendor Advisory)

Frequently asked questions

What is CVE-2020-8280?: CVE-2020-8280 is a medium-severity vulnerability in Nextcloud Contacts, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2021-01-06.
How severe is CVE-2020-8280?: Medium severity. CVSS v3 base score is 5.4 out of 10.