CVE-2026-26304: Mattermost fails to verify run_create permission for empty playbookId

CVE-2026-26304 · Severity: low · CVSS 3.1 · Published 2026-03-23

Mattermost fails to verify run_create permission for empty playbookId in github.com/mattermost/mattermost-plugin-playbooks

Technologies: github.com/mattermost/mattermost-plugin-playbooks (Go). Vendors: Go.

Quick answers

Is CVE-2026-26304 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-26304 being exploited in the wild.
How severe is CVE-2026-26304?
Low severity, with a CVSS score of 3.1, published 23 March 2026.
Which products and versions are affected?
github.com/mattermost/mattermost-plugin-playbooks (Go) SEMVER:introduced=0,fixed=1.41.1-0.20260316224925-705f54a81841.
Is there a fix for CVE-2026-26304?
Yes. github.com/mattermost/mattermost-plugin-playbooks (Go): upgrade to 1.41.1-0.20260316224925-705f54a81841 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
Am I affected by CVE-2026-26304?
Check whether you run github.com/mattermost/mattermost-plugin-playbooks (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • github.com/mattermost/mattermost-plugin-playbooks (Go): upgrade to 1.41.1-0.20260316224925-705f54a81841 or later
    go get github.com/mattermost/mattermost-plugin-playbooks@v1.41.1-0.20260316224925-705f54a81841

Affected products

  • github.com/mattermost/mattermost-plugin-playbooks (Go) SEMVER:introduced=0,fixed=1.41.1-0.20260316224925-705f54a81841

Identifiers

  • CVE-2026-26304
  • GHSA-4pmx-622h-x359
  • GO-2026-4812

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