# CVE-2026-26304: mattermost-plugin — Fix Available

🐹

🐹 Go

Not in CISA KEV

MEDIUM severity

# CVE-2026-26304 — mattermost-plugin-playboo…

MEDIUM [Fix: mattermost/mattermost-plugin-playbooks@705f54a](https://github.com/mattermost/mattermost-plugin-playbooks/commit/705f54a818410f3612df3865bfde608ed471037e)

CVE-2026-26304 is a medium-severity (CVSS 4.3) CWE-863 vulnerability in github.com/mattermost/mattermost-plugin-playbooks. A fix is available for github.com/mattermost/mattermost-plugin-playbooks — see the affected versions and patch details below.

Permission Bypass in Playbook Run Creation

Also known as[GHSA-4pmx-622h-x359](/vulnerability/GHSA-4pmx-622h-x359)GO-2026-4812

Published

Mar 16, 2026

Updated

Nov 7, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 7, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

## Exploitation Status

### No confirmed exploitation observed yet

-   CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-26304.

## EPSS Exploitation Probability

[via FIRST.org ↗](https://www.first.org/epss/)

0.2%probability of exploitation in next 30 days

Lower Risk+0.00%

Lower risk than most CVEs6th percentile — riskier than 6% of all scored CVEsHighest risk

0.00%0.25%0.50%0.75%0.0%0.2%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from [FIRST.org EPSS](https://www.first.org/epss/).

## How urgent is this, really

## Where this sits among everything scored

## Real-World Exposure

1 pkg affected

🐹`github.com/mattermost/mattermost-plugin-playbooks`

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

## 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

## Affected Packages

1 total 1 fixed

Ecosystem

Package

Vulnerable range

Fix

🐹Go

`github.com/mattermost/mattermost-plugin-playbooks` 

all versions

1.41.1-0.20260316224925-705f54a81841`go get github.com/mattermost/mattermost-plugin-playbooks@v1.41.1-0.20260316224925-705f54a81841`

## Affected Products

1 product · 2 configurations

Application

`mattermost server`mattermost

≥ 11.3.0 && < 11.3.1

range

## Detection & mitigation playbook

Open-source dependency

1.  ### Detect
    
    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/mattermost/mattermost-plugin-playbooks, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
    
2.  ### Fix
    
    Update github.com/mattermost/mattermost-plugin-playbooks to 1.41.1-0.20260316224925-705f54a81841 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-26304 is resolved across your whole dependency graph.
    
3.  ### Workarounds
    
    Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.
    

## Frequently Asked Questions

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

O3 Security · Impact-Aware SCA

### Is CVE-2026-26304 in your dependencies?

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