# CVE-2023-3613: Guest accounts invited and added to channels by Welcomebot plugin

> The Mattermost WelcomeBot plugin allows guest accounts to be added to channels without proper validation, potentially exposing channel data to unauthorized users.

- **Severity:** Low 3.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N`)
- **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:** Yes
- **Published:** 17 Jul 2023
- **Updated:** 21 Oct 2024
- **Also known as:** BIT-mattermost-2023-3613, GHSA-v326-937j-3p86

## What is CVE-2023-3613?

CVE-2023-3613 is a low-severity missing authorization vulnerability in Mattermost Mattermost Server, published on 17 Jul 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

Mattermost WelcomeBot plugin fails to to validate the membership status when inviting or adding users to channels allowing guest accounts to be added or invited to channels by default.

Weakness: CWE-863 (Incorrect Authorization)

## Which versions are affected by CVE-2023-3613?

1 open source package ship an affected version, including mattermost. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `mattermost` | Bitnami | All versions | 7.8.6, 7.10.3 |

Products: Mattermost Mattermost Server.

## How do I fix CVE-2023-3613?

Upgrade mattermost to a fixed version for your release line: 7.8.6 or 7.10.3.

## Is CVE-2023-3613 being exploited?

There is no known exploitation of CVE-2023-3613 in the wild and no public exploit code.

## Other vulnerabilities in Mattermost Mattermost Server

- [CVE-2025-12419](https://insights.sbomify.com/CVE-2025-12419/): Account takeover on OAuth/OpenID-enabled servers (critical 9.9)
- [CVE-2025-12421](https://insights.sbomify.com/CVE-2025-12421/): Account Takeover via Code Exchange Endpoint (critical 9.9)
- [CVE-2025-4981](https://insights.sbomify.com/CVE-2025-4981/): Path Traversal Leading to RCE by Any Authenticated Mattermost User (critical 9.9)
- [CVE-2025-20051](https://insights.sbomify.com/CVE-2025-20051/): Arbitrary file read via block duplication in Mattermost Boards (critical 9.9)
- [CVE-2025-25279](https://insights.sbomify.com/CVE-2025-25279/): Arbitrary file read in Mattermost Boards via import & export board archive (critical 9.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-3613 and fix it if it is affected.

What it is: CVE-2023-3613 is a low-severity missing authorization vulnerability in Mattermost Mattermost Server, published on 17 Jul 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-2023-3613 in the wild and no public exploit code.

Affected packages and fixed versions:
- mattermost (Bitnami): affected all versions; fixed in 7.8.6, 7.10.3

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-2023-3613/ (Markdown: https://insights.sbomify.com/CVE-2023-3613/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-3613
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-3613
- OSV: https://osv.dev/vulnerability/CVE-2023-3613

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-3613/
Summaries are generated and may contain mistakes; the official description above is the record.