What is CVE-2019-15621?

CVE-2019-15621 is a medium-severity vulnerability in Nextcloud Server, classified under Improper Preservation of Permissions. CVSS score: 6.5/10. Published 2020-02-04.

How severe is CVE-2019-15621?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Vulnerability in Nextcloud Server

CVE-2019-15621

Improper permissions preservation in Nextcloud Server 16.0.1 causes sharees to be able to reshare with write permissions when sharing the mount point of a share they received, as a public link.

Published 2020-02-04 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N.

EPSS exploit prediction

EPSS: 0.011 (63.0th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 63rd percentile — 63.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.011 · newest: 0.011 · change: 0.000

Affected products

Nextcloud Server
Nextcloud Server — versions 16.0.2

Weakness classification (CWE)

CWE-281 — Improper Preservation of Permissions

References

hackerone.com/reports/619484 (Permissions Required)
nextcloud.com/security/advisory/ (Vendor Advisory)
lists.opensuse.org/opensuse-security-announce/2020-02/msg00019.html (vendor-advisory)
lists.opensuse.org/opensuse-security-announce/2020-02/msg00022.html (vendor-advisory)

Frequently asked questions

What is CVE-2019-15621?: CVE-2019-15621 is a medium-severity vulnerability in Nextcloud Server, classified under Improper Preservation of Permissions. CVSS score: 6.5/10. Published 2020-02-04.
How severe is CVE-2019-15621?: Medium severity. CVSS v3 base score is 6.5 out of 10.