What is CVE-2020-8235?

CVE-2020-8235 is a medium-severity vulnerability in Nextcloud Deck, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 4.3/10. Published 2020-10-05.

How severe is CVE-2020-8235?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Auth bypass in Nextcloud Deck

CVE-2020-8235

Missing access control in Nextcloud Deck 1.0.4 caused an insecure direct object reference allowing an attacker to view all attachments.

Vulnerability class: IDOR (Insecure Direct Object Reference)

Published 2020-10-05 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.

EPSS exploit prediction

EPSS: 0.008 (54.2th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 54th percentile — 54.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.008 · newest: 0.008 · change: 0.000

Affected products

Nextcloud Deck — versions 1.0.4
Nextcloud Deck App — versions Fixed in 1.0.5

Weakness classification (CWE)

CWE-639 — Authorization Bypass Through User-Controlled Key

References

hackerone.com/reports/916704 (Exploit, Third Party Advisory)
nextcloud.com/security/advisory/ (Vendor Advisory)

Frequently asked questions

What is CVE-2020-8235?: CVE-2020-8235 is a medium-severity vulnerability in Nextcloud Deck, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 4.3/10. Published 2020-10-05.
How severe is CVE-2020-8235?: Medium severity. CVSS v3 base score is 4.3 out of 10.