What is CVE-2018-16465?

CVE-2018-16465 is a medium-severity vulnerability in Nextcloud Server, classified under Improper Authentication. CVSS score: 5.3/10. Published 2018-10-30.

How severe is CVE-2018-16465?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Auth bypass in Nextcloud Server

CVE-2018-16465

Missing state in Nextcloud Server prior to 14.0.0 would not enforce the use of a second factor at login if the the provider of the second factor failed to load.

Vulnerability class: Broken Authentication

Published 2018-10-30 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N.

EPSS exploit prediction

EPSS: 0.008 (55.2th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 55th percentile — 55.2% 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 Server
Nextcloud Server — versions <14.0.0

Weakness classification (CWE)

CWE-287 — Improper Authentication

References

hackerone.com/reports/317711 (Third Party Advisory)
nextcloud.com/security/advisory/ (Vendor Advisory)

Frequently asked questions

What is CVE-2018-16465?: CVE-2018-16465 is a medium-severity vulnerability in Nextcloud Server, classified under Improper Authentication. CVSS score: 5.3/10. Published 2018-10-30.
How severe is CVE-2018-16465?: Medium severity. CVSS v3 base score is 5.3 out of 10.