Deleting users with certain names caused system files to be deleted.

published 2021-02-09 5 y ago modified 2026-06-17 4 mo ago also EUVD-2020-21043

cvss: 9.1; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 1.3%; EPSS 1.3% chance of exploitation in 30 days, percentile 69%
public exploits: 0; none known

Deleting users with certain names caused system files to be deleted. Risk is higher for systems which allow users to register themselves and have the data directory in the web root. This affects ownCloud/core versions < 10.6.

Patch / fix

fixed in 1

owncloud owncloud 10.6.0

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-2020-28645 updated 2025-11-21 cvss 6.8

owncloud: deleting users with certain names caused system files to be deleted

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

1.26% chance of exploitation in the next 30 days, higher than 69% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
NVD	3.1	9.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
NVD	2.0	5.0	AV:N/AC:L/Au:N/C:N/I:P/A:N

Classification

Weakness

CWE-20 Improper Input Validation

References

owncloud.com /security-advisories/missing-user-validation-leading-to-information-disclosure/
vendor-advisory

Sources

CVE List CVE-2020-28645
NVD CVE-2020-28645

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