---
id: CVE-2025-35965
aliases:
  - GHSA-689c-xq7x-xjwf
  - GO-2025-3643
title: >-
  Mattermost Playbooks fails to validate the uniqueness and quantity of task
  actions
summary: >-
  Mattermost Playbooks fails to validate the uniqueness and quantity of task
  actions
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
vendor: mattermost
product: github.com/mattermost/mattermost/server/v8
ecosystem: go
affected:
  - >-
    github.com/mattermost/mattermost/server/v8 <
    8.0.0-20250218121836-2b5275d87136
  - github.com/mattermost/mattermost-plugin-playbooks >= 2.0.0
  - github.com/mattermost/mattermost/server/v8 >= 10.4.0
  - github.com/mattermost/mattermost/server/v8 >= 10.5.0
  - github.com/mattermost/mattermost/server/v8 >= 9.11.0
  - github.com/mattermost/mattermost-plugin-playbooks < 1.41.0
patched:
  - github.com/mattermost/mattermost/server/v8 8.0.0-20250218121836-2b5275d87136
  - github.com/mattermost/mattermost-plugin-playbooks 1.41.0
published: '2025-04-24'
updated: '2026-09-10'
sourceUpdated: '2026-09-10T03:50:23.660878170Z'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-689c-xq7x-xjwf'
references:
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2025-35965'
  - url: >-
      https://github.com/mattermost/mattermost-plugin-playbooks/commit/bf2633dad09f5768ce2bea4b7c5ffb74050052a8
  - url: >-
      https://github.com/mattermost/mattermost/commit/2b5275d87136f07e016c8eca09a2f004b31afc8a
  - url: 'https://github.com/mattermost/mattermost-plugin-playbooks'
  - url: 'https://mattermost.com/security-updates'
tags:
  - osv
  - go
epss: 0.00403
epssPercentile: 0.34406
ingestedAt: '2026-09-12T03:13:01.757Z'
---

## Overview

Mattermost versions 10.4.x <= 10.4.2, 10.5.x <= 10.5.0, 9.11.x <= 9.11.10 fail to validate the uniqueness and quantity of task actions within the UpdateRunTaskActions GraphQL operation, which allows an attacker to create task items containing an excessive number of actions triggered by specific posts, overloading the server and leading to a denial-of-service (DoS) condition.

## Affected packages

- `github.com/mattermost/mattermost/server/v8 < 8.0.0-20250218121836-2b5275d87136`
- `github.com/mattermost/mattermost-plugin-playbooks >= 2.0.0`
- `github.com/mattermost/mattermost/server/v8 >= 10.4.0`
- `github.com/mattermost/mattermost/server/v8 >= 10.5.0`
- `github.com/mattermost/mattermost/server/v8 >= 9.11.0`
- `github.com/mattermost/mattermost-plugin-playbooks < 1.41.0`

## Remediation

Upgrade to a patched release:

- `github.com/mattermost/mattermost/server/v8 8.0.0-20250218121836-2b5275d87136`
- `github.com/mattermost/mattermost-plugin-playbooks 1.41.0`