A missing check in Nextcloud Server 17.0.0 allowed an attacker to set up a new second factor when trying to login.

published 2020-02-04 6 y ago modified 2026-06-17 4 mo ago also EUVD-2019-6574

cvss: 5.4; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 0.6%; EPSS 0.6% chance of exploitation in 30 days, percentile 49%
public exploits: 0; none known

Patch / fix

fixed in 1

nextcloud nextcloud_server 17.0.1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2019-15617 updated 2025-11-21

nextcloud: Several CVEs fixed in nextcloud 15, 16 and 17

Red Hat All currently supported Red Hat products
not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.61% chance of exploitation in the next 30 days, higher than 49% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
NVD	3.1	5.4	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
NVD	2.0	5.5	AV:N/AC:L/Au:S/C:P/I:P/A:N

Affected products

n/a Nextcloud Server

Classification

Weakness

CWE-287 Improper Authentication

References

nextcloud.com /security/advisory/?id=NC-SA-2020-006
vendor-advisory
hackerone.com /reports/722748
permissions-required

Sources

CVE List CVE-2019-15617
NVD CVE-2019-15617

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary