CVE-2021-32655Network attack vector

Read access via Files Drop share conversion

Published Jun 1, 2021 · Updated Aug 3, 2024

Improper data handling in Nextcloud Server before 19.0.11, 20.0.10, and 21.0.2 allows remote authenticated users to gain read access. The sharing panel's permission-update path treats removal of Create permission from an unexpected federated Files Drop share as a request to grant Read permission. Exploitation requires conversion of a Files Drop link and interaction by the sharing user, and the reported consequence is unauthorized reading of shared data.

CVSS severity3.5
Low
EPSS probability1.03%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper data handling in Nextcloud Server before 19.0.11, 20.0.10, and 21.0.2 allows remote authenticated users to gain read access. The sharing panel's permission-update path treats removal of Create permission from an unexpected federated Files Drop share as a request to grant Read permission. Exploitation requires conversion of a Files Drop link and interaction by the sharing user, and the reported consequence is unauthorized reading of shared data.

The record

CVE
CVE-2021-32655
Published
Jun 1, 2021
Updated
Aug 3, 2024
Vendor
Nextcloud GmbH
Product
Nextcloud Security Advisories
Classifications
CWE-241, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 1, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 19.0.11
  2. Affected versionversion=>= 20.0.0, < 20.0.10
  3. Affected versionversion=>= 21.0.0, < 21.0.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Nextcloud GmbH · Nextcloud Security Advisoriesversion=< 19.0.11; version=>= 20.0.0, < 20.0.10; version=>= 21.0.0, < 21.0.2

Published CVSS scores

3.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N
3.5NIST NVDAV:N/AC:M/Au:S/C:P/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-241Improper Handling of Unexpected Data Type
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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