# CVE-2023-30539: Users can set up workflows using restricted and invisible system tags in Nextcloud

> Attackers can bypass access controls by using restricted system tags in workflows, potentially granting unauthorized access to files.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 17 Apr 2023
- **Updated:** 5 Feb 2025
- **Also known as:** GHSA-3m2f-v8x7-9w99

## What is CVE-2023-30539?

CVE-2023-30539 is a medium-severity missing authorization vulnerability in Nextcloud Nextcloud Server, published on 17 Apr 2023. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

Nextcloud is a personal home server system. Depending on the set up tags and other workflows this issue can be used to limit access of others or being able to grant them access when there are system tag based files access control or files retention rules. It is recommended that the Nextcloud Server is upgraded to 24.0.11 or 25.0.5, the Nextcloud Enterprise Server to 21.0.9.11, 22.2.10.11, 23.0.12.6, 24.0.11 or 25.0.5, and the Nextcloud Files automated tagging app to 1.11.1, 1.12.1, 1.13.1, 1.14.2, 1.15.3 or 1.16.1. Users unable to upgrade should disable all workflow related apps. Users are advised to upgrade.

Weakness: CWE-284 (Improper Access Control)

## Which versions are affected by CVE-2023-30539?

It affects 2 products.


Products: Nextcloud Nextcloud Files Automated Tagging, Nextcloud Nextcloud Server.

## How do I fix CVE-2023-30539?

No fix has been published for CVE-2023-30539 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-30539 being exploited?

There is no known exploitation of CVE-2023-30539 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-30539 and fix it if it is affected.

What it is: CVE-2023-30539 is a medium-severity missing authorization vulnerability in Nextcloud Nextcloud Server, published on 17 Apr 2023. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2023-30539 in the wild and no public exploit code.

Affected product: Nextcloud Nextcloud Server. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2023-30539/ (Markdown: https://insights.sbomify.com/CVE-2023-30539/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-30539
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-30539
- OSV: https://osv.dev/vulnerability/CVE-2023-30539

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-30539/
Summaries are generated and may contain mistakes; the official description above is the record.