What is CVE-2019-5451?

CVE-2019-5451 is a medium-severity vulnerability in Nextcloud Server, classified under Authentication Bypass Using an Alternate Path or Channel. CVSS score: 4.6/10. Published 2019-07-30.

How severe is CVE-2019-5451?

Medium severity. CVSS v3 base score is 4.6 out of 10.

Auth bypass in Nextcloud Server

CVE-2019-5451

Bypass lock protection in the Nextcloud Android app prior to version 3.6.1 allows accessing the files when repeatedly opening and closing the app in a very short time.

Published 2019-07-30 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.6 (Medium). Vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.004 (29.9th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 30th percentile — 29.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000

Affected products

Nextcloud Server
Com.nextcloud.client — versions 3.6.1

Weakness classification (CWE)

References

hackerone.com/reports/507172 (Third Party Advisory)

Frequently asked questions

What is CVE-2019-5451?: CVE-2019-5451 is a medium-severity vulnerability in Nextcloud Server, classified under Authentication Bypass Using an Alternate Path or Channel. CVSS score: 4.6/10. Published 2019-07-30.
How severe is CVE-2019-5451?: Medium severity. CVSS v3 base score is 4.6 out of 10.