# CVE-2024-39807: Channel IDs of archived/restored channels leaked via webhook events

> Attackers monitoring webhook events can retrieve channel IDs of archived or restored channels in Mattermost, exposing internal structure.

- **Severity:** Low 3.1 (`CVSS:3.1/AV:N/AC:H/PR:L/UI:N/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:** Not needed
- **Fix available:** No
- **Published:** 3 Jul 2024
- **Updated:** 2 Aug 2024
- **Also known as:** GHSA-fc2h-j9fj-rh35

## What is CVE-2024-39807?

CVE-2024-39807 is a low-severity vulnerability in Mattermost Mattermost, published on 3 Jul 2024. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Mattermost versions 9.5.x <= 9.5.5 and 9.8.0 fail to properly sanitize the recipients of a webhook event which allows an attacker monitoring webhook events to retrieve the channel IDs of archived or restored channels.

Weakness: CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor)

## Which versions are affected by CVE-2024-39807?

It affects 1 product.


Products: Mattermost Mattermost.

## How do I fix CVE-2024-39807?

No fix has been published for CVE-2024-39807 yet. Limit exposure of the affected software until one is available.

## Is CVE-2024-39807 being exploited?

There is no known exploitation of CVE-2024-39807 in the wild and no public exploit code.

## Other vulnerabilities in Mattermost Mattermost

- [CVE-2019-20851](https://insights.sbomify.com/CVE-2019-20851/): Path traversal in n/a (critical 9.1)
- [CVE-2024-39274](https://insights.sbomify.com/CVE-2024-39274/): Malicious remote can add users to arbitrary teams and channels (high 8.7)
- [CVE-2024-39777](https://insights.sbomify.com/CVE-2024-39777/): Malicious remote can invite itself to an arbitrary local channel (high 8.7)
- [CVE-2024-39830](https://insights.sbomify.com/CVE-2024-39830/): Timing attack during remote cluster token comparison when shared channels are enabled (high 8.1)
- [CVE-2023-3615](https://insights.sbomify.com/CVE-2023-3615/): Lack of server certificate validation in websockets connection (high 8.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-39807 and fix it if it is affected.

What it is: CVE-2024-39807 is a low-severity vulnerability in Mattermost Mattermost, published on 3 Jul 2024. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2024-39807 in the wild and no public exploit code.

Affected product: Mattermost Mattermost. 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-2024-39807/ (Markdown: https://insights.sbomify.com/CVE-2024-39807/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-39807
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-39807
- OSV: https://osv.dev/vulnerability/CVE-2024-39807

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-39807/
Summaries are generated and may contain mistakes; the official description above is the record.