Vulnerability in Nextcloud Collectives

CVE-2026-77166

The emoji field in the page emoji update endpoint does not properly validate user input. By injecting long text and line breaks, the sidebar layout becomes broken and can hide other items.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 2.4 (Low). Vector: CVSS:3.0/AV:N/AC:L/PR:H/UI:R/S:U/C:N/I:L/A:N.

EPSS exploit prediction

EPSS: 0.003 (21.0th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 21st percentile — 21.0% 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-2026-77166: 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-2026-77166?
CVE-2026-77166 is a low-severity vulnerability in Nextcloud Collectives, classified under CWE-840. CVSS score: 2.4/10. Published 2026-09-21.
How severe is CVE-2026-77166?
Low severity. CVSS v3 base score is 2.4 out of 10.