CVE-2025-66545Public exploitNetwork attack vector

Unauthorized file restoration via wrong-path permission check

Published Dec 5, 2025 · Updated Dec 8, 2025

Improper authorization in Nextcloud Groupfolders allows remote authenticated users with read-only access to restore deleted files. The TrashBackend restoreItem method checks update permission against the item’s trash-bin path rather than the restored node’s unjailed destination path. Exploitation requires read-only Team Folder access and a deleted file in trash; restoration modifies stored data without write permission.

CVSS severity3.5
Low
EPSS probability0.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authorization in Nextcloud Groupfolders allows remote authenticated users with read-only access to restore deleted files. The TrashBackend restoreItem method checks update permission against the item’s trash-bin path rather than the restored node’s unjailed destination path. Exploitation requires read-only Team Folder access and a deleted file in trash; restoration modifies stored data without write permission.

The record

CVE
CVE-2025-66545
Published
Dec 5, 2025
Updated
Dec 8, 2025
Vendor
Nextcloud GmbH
Product
Security Advisories
Classifications
CWE-707, T1565.001
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 5, 2025CVE publishedPublication date reported by the CVE source.
  2. Dec 8, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=< 14.0.11
  2. Affected versionversion=>= 15.0.0-beta1, < 15.3.12
  3. Affected versionversion=>= 16.0.0, < 16.0.15
  4. Affected versionversion=>= 17.0.0-beta.1, < 17.0.14
  5. Affected versionversion=>= 18.0.0-beta.1, < 18.1.8
  6. Affected versionversion=>= 19.0.0-alpha.1, < 19.1.8
  7. Affected versionversion=>= 20.0.0, < 20.1.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Nextcloud GmbH · Security Advisoriesversion=< 14.0.11; version=>= 15.0.0-beta1, < 15.3.12; version=>= 16.0.0, < 16.0.15; version=>= 17.0.0-beta.1, < 17.0.14; version=>= 18.0.0-beta.1, < 18.1.8; version=>= 19.0.0-alpha.1, < 19.1.8; version=>= 20.0.0, < 20.1.2

Published CVSS scores

3.5GitHubCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/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 exploitPublished

Weakness, pattern, technique

CWE-707Improper Neutralization
T1565.001Stored Data Manipulation

Public exploit references

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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