CVE-2021-41241Network attack vector

Authenticated file disclosure via ACL-bypassing folder copy

Published Mar 8, 2022 · Updated Apr 23, 2025

Incorrect authorization in affected Nextcloud Server releases allows remote authenticated users to read restricted groupfolder files by copying them. The groupfolder copy path invokes Local::copyFromStorage rather than the ACL-aware Common::copyFromStorage operation, so descendant permission checks are skipped. An account with access to a groupfolder root can copy the entire folder into a controlled location and expose protected subfolders in releases before 20.0.14, 21.0.0 through 21.0.5, and 22.2.0.

CVSS severity4.3
Medium
EPSS probability0.85%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect authorization in affected Nextcloud Server releases allows remote authenticated users to read restricted groupfolder files by copying them. The groupfolder copy path invokes Local::copyFromStorage rather than the ACL-aware Common::copyFromStorage operation, so descendant permission checks are skipped. An account with access to a groupfolder root can copy the entire folder into a controlled location and expose protected subfolders in releases before 20.0.14, 21.0.0 through 21.0.5, and 22.2.0.

The record

CVE
CVE-2021-41241
Published
Mar 8, 2022
Updated
Apr 23, 2025
Vendor
Nextcloud GmbH
Product
Security Advisories
Classifications
CWE-863, CWE-862, T1213
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 8, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 23, 2025Record 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=< 20.0.14
  2. Affected versionversion=>= 21.0.0, < 21.0.6
  3. Affected versionversion=>= 22.2.0, < 22.2.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Nextcloud GmbH · Security Advisoriesversion=< 20.0.14; version=>= 21.0.0, < 21.0.6; version=>= 22.2.0, < 22.2.1

Published CVSS scores

4.3GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
4.0NIST NVDAV:N/AC:L/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-863Incorrect Authorization
CWE-862Missing Authorization
T1213Data from Information Repositories

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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