What is CVE-2021-32766?

CVE-2021-32766 is a medium-severity vulnerability in Nextcloud Server, classified under Generation of Error Message Containing Sensitive Information. CVSS score: 5.3/10. Published 2021-09-07.

How severe is CVE-2021-32766?

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

Information disclosure in Nextcloud Server

CVE-2021-32766

Nextcloud Text is an open source plaintext editing application which ships with the nextcloud server. In affected versions the Nextcloud Text application returned different error messages depending on whether a folder existed in a public link share. This is problematic in case the public link share has been created with "Upload Only" privileges. (aka "File Drop"). A link share recipient is not expected to see which folders or files exist in a "File Drop" share. Using this vulnerability an attacker is able to enumerate folders in such a share. Exploitation requires that the attacker has access to a valid affected "File Drop" link share. It is recommended that the Nextcloud Server is upgraded to 20.0.12, 21.0.4 or 22.0.1. Users who are unable to upgrade are advised to disable the Nextcloud Text application in the app settings.

Published 2021-09-07 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N.

EPSS exploit prediction

EPSS: 0.013 (70.2th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 70th percentile — 70.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.013 · newest: 0.013 · change: 0.000

Affected products

Nextcloud Server
Nextcloud Security-Advisories — versions < 20.0.12, >= 21.0.0, < 21.0.4, >= 22.0.0, < 22.0.1

Weakness classification (CWE)

CWE-209 — Generation of Error Message Containing Sensitive Information

References

github.com/nextcloud/security-advisories/security/advisories/GHSA-gcf3-3wmc-88jr (Third Party Advisory)
github.com/nextcloud/text/pull/1716 (Patch, Third Party Advisory)
hackerone.com/reports/1253475 (Permissions Required, Third Party Advisory)

Frequently asked questions

What is CVE-2021-32766?: CVE-2021-32766 is a medium-severity vulnerability in Nextcloud Server, classified under Generation of Error Message Containing Sensitive Information. CVSS score: 5.3/10. Published 2021-09-07.
How severe is CVE-2021-32766?: Medium severity. CVSS v3 base score is 5.3 out of 10.