CVE-2023-30539Network attack vector

File access manipulation via unchecked system tags

Published Apr 17, 2023 · Updated Feb 5, 2025

Improper access control in Nextcloud Server and Files Automated Tagging allows remote authenticated users to alter file access through workflows. Workflow rule creation accepted restricted or invisible system-tag identifiers without validating the tags' visibility and assignment restrictions. Exploitation requires an authenticated account and user interaction; consequences depend on configured tag-based file access control or retention rules.

CVSS severity6.5
Medium
EPSS probability0.63%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper access control in Nextcloud Server and Files Automated Tagging allows remote authenticated users to alter file access through workflows. Workflow rule creation accepted restricted or invisible system-tag identifiers without validating the tags' visibility and assignment restrictions. Exploitation requires an authenticated account and user interaction; consequences depend on configured tag-based file access control or retention rules.

The record

CVE
CVE-2023-30539
Published
Apr 17, 2023
Updated
Feb 5, 2025
Vendor
Nextcloud GmbH
Product
Security Advisories
Classifications
CWE-284, T1565.001
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 17, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 5, 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=Nextcloud Files automated tagging: >= 1.11.0, < 1.11.1
  2. Affected versionversion=Nextcloud Files automated tagging: >= 1.12.0, < 1.12.1
  3. Affected versionversion=Nextcloud Files automated tagging: >= 1.13.0, < 1.13.1
  4. Affected versionversion=Nextcloud Files automated tagging: >= 1.14.0, < 1.14.2
  5. Affected versionversion=Nextcloud Files automated tagging: >= 1.15.0, < 1.15.3
  6. Affected versionversion=Nextcloud Files automated tagging: >= 1.16.0, < 1.16.1
  7. Affected versionversion=Nextcloud Server: < 24.0.11
  8. Affected versionversion=Nextcloud Server: >= 25.0.0, < 25.0.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Nextcloud GmbH · Security Advisoriesversion=Nextcloud Files automated tagging: >= 1.11.0, < 1.11.1; version=Nextcloud Files automated tagging: >= 1.12.0, < 1.12.1; version=Nextcloud Files automated tagging: >= 1.13.0, < 1.13.1; version=Nextcloud Files automated tagging: >= 1.14.0, < 1.14.2; version=Nextcloud Files automated tagging: >= 1.15.0, < 1.15.3; version=Nextcloud Files automated tagging: >= 1.16.0, < 1.16.1; version=Nextcloud Server: < 24.0.11; version=Nextcloud Server: >= 25.0.0, < 25.0.5

Published CVSS scores

8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
6.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L

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-284Improper Access Control
T1565.001Stored Data Manipulation

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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