Vulnerability in Nextcloud Deck

CVE-2026-77170

The Deck config API allows authenticated users to set board-scoped configuration keys for arbitrary board IDs without validating whether the user owns or has permission to manage the referenced board.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N.

EPSS exploit prediction

EPSS: 0.003 (19.2th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 19th percentile — 19.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-77170: held from 0.003 to 0.003.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-77170?
CVE-2026-77170 is a medium-severity vulnerability in Nextcloud Deck, classified under Improper Access Control. CVSS score: 4.3/10. Published 2026-09-18.
How severe is CVE-2026-77170?
Medium severity. CVSS v3 base score is 4.3 out of 10.