Mattermost up to 10.11.22/11.7.7/11.8.4/11.9.0 Playbooks input validation

Summaryinfo

A vulnerability was found in Mattermost up to 10.11.22/11.7.7/11.8.4/11.9.0 and classified as problematic. This affects an unknown part of the component Playbooks. Such manipulation leads to input validation. This vulnerability is documented as CVE-2026-9812. The attack can be executed remotely. There is not any exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in Mattermost up to 10.11.22/11.7.7/11.8.4/11.9.0. Affected by this issue is an unknown code of the component Playbooks. The manipulation with an unknown input leads to a input validation vulnerability. Using CWE to declare the problem leads to CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. Impacted is availability. CVE summarizes:

Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7, 10.11.x <= 10.11.22 fail to validate that a property field belongs to the specified run before updating its value which allows an authenticated user with run property-management access to crash the Playbooks plugin via a REST request referencing a property field that belongs to a different run. Mattermost Advisory ID: MMSA-2026-00684

The advisory is available at mattermost.com. This vulnerability is handled as CVE-2026-9812 since 05/28/2026. The exploitation is known to be easy. The attack may be launched remotely. The technical details are unknown and an exploit is not available.

Upgrading to version 10.11.23, 11.7.8, 11.8.5, 11.9.1 or 11.10.0 eliminates this vulnerability.

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Productinfo

Type

• Groupware Software

Name

• Mattermost

Version

• 10.11.0
• 10.11.1
• 10.11.2
• 10.11.3
• 10.11.4
• 10.11.5
• 10.11.6
• 10.11.7
• 10.11.8
• 10.11.9
• 10.11.10
• 10.11.11
• 10.11.12
• 10.11.13
• 10.11.14
• 10.11.15
• 10.11.16
• 10.11.17
• 10.11.18
• 10.11.19
• 10.11.20
• 10.11.21
• 10.11.22
• 11.0
• 11.1
• 11.2
• 11.3
• 11.4
• 11.5
• 11.6
• 11.7
• 11.7.0
• 11.7.1
• 11.7.2
• 11.7.3
• 11.7.4
• 11.7.5
• 11.7.6
• 11.7.7
• 11.8
• 11.8.0
• 11.8.1
• 11.8.2
• 11.8.3
• 11.8.4
• 11.9.0

License

• open-source

CPE 2.3info

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CPE 2.2info

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