# CVE-2025-0503: Leaked User IDs and Metadata of Deleted DMs

> Attackers can infer user IDs and metadata from deleted direct messages in Mattermost if DMs were manually marked as deleted in the database.

- **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:** 14 Feb 2025
- **Updated:** 14 Feb 2025
- **Also known as:** GHSA-cc72-wc5x-7wmj

## What is CVE-2025-0503?

CVE-2025-0503 is a low-severity vulnerability in Mattermost Mattermost Server, published on 14 Feb 2025. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Mattermost versions 9.11.x <= 9.11.6 fail to filter out DMs from the deleted channels endpoint which allows an attacker to infer user IDs and other metadata from deleted DMs if someone had manually marked DMs as deleted in the database.

Weakness: CWE-754 (Improper Check for Unusual or Exceptional Conditions)

## Which versions are affected by CVE-2025-0503?

It affects 1 product.


Products: Mattermost Mattermost Server.

## How do I fix CVE-2025-0503?

No fix has been published for CVE-2025-0503 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-0503 being exploited?

There is no known exploitation of CVE-2025-0503 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-2025-0503 and fix it if it is affected.

What it is: CVE-2025-0503 is a low-severity vulnerability in Mattermost Mattermost Server, published on 14 Feb 2025. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-0503 in the wild and no public exploit code.

Affected product: Mattermost Mattermost 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-2025-0503/ (Markdown: https://insights.sbomify.com/CVE-2025-0503/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-0503
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-0503
- OSV: https://osv.dev/vulnerability/CVE-2025-0503

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-0503/
Summaries are generated and may contain mistakes; the official description above is the record.