# CVE-2026-34584: listmonk: Broken Access Control in CSV Import (Unauthorized List Assignment)

> Unauthorized users can access and modify mailing lists they lack permissions for in multi-user environments.

- **Severity:** Medium 5.4 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 2 Apr 2026
- **Updated:** 2 Apr 2026
- **Also known as:** GHSA-85j8-5c6w-gcpv

## What is CVE-2026-34584?

CVE-2026-34584 is a medium-severity missing authorization vulnerability in knadh listmonk, published on 2 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

listmonk is a standalone, self-hosted, newsletter and mailing list manager. From version 4.1.0 to before version 6.1.0, bugs in list permission checks allows users in a multi-user environment to access to lists (which they don't have access to) under different scenarios. This only affects multi-user environments with untrusted users. This issue has been patched in version 6.1.0.

Weakness: CWE-639 (Authorization Bypass Through User-Controlled Key)

## Which versions are affected by CVE-2026-34584?

It affects 1 product.


Products: Nadh Listmonk.

## How do I fix CVE-2026-34584?

No fix has been published for CVE-2026-34584 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-34584 being exploited?

There is no known exploitation of CVE-2026-34584 in the wild and no public exploit code.

## Other vulnerabilities in knadh listmonk

- [CVE-2025-49136](https://insights.sbomify.com/CVE-2025-49136/): listmonk's Sprig template Injection vulnerability leads to reading of Environment Variable for low privilege user (critical 9.1)
- [CVE-2025-58430](https://insights.sbomify.com/CVE-2025-58430/): listmonk Vulnerable to CSRF to XSS Chain That Can Lead to Admin Account Takeover (high 8.6)
- [CVE-2026-34828](https://insights.sbomify.com/CVE-2026-34828/): listmonk: Active sessions remain valid after password reset and password change (high 7.1)
- [CVE-2025-46011](https://insights.sbomify.com/CVE-2025-46011/): SQL injection in n/a (medium 6.5)
- [CVE-2026-21483](https://insights.sbomify.com/CVE-2026-21483/): listmonk Vulnerable to Stored XSS Leading to Admin Account Takeover (medium 5.4)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-34584 and fix it if it is affected.

What it is: CVE-2026-34584 is a medium-severity missing authorization vulnerability in knadh listmonk, published on 2 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-34584 in the wild and no public exploit code.

Affected product: knadh listmonk. 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-2026-34584/ (Markdown: https://insights.sbomify.com/CVE-2026-34584/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-34584
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-34584
- OSV: https://osv.dev/vulnerability/CVE-2026-34584

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-34584/
Summaries are generated and may contain mistakes; the official description above is the record.