Mattermost up to 10.11.19/11.6.4/11.7.2/11.7.x Channel Patch API improper synchronization

Summaryinfo

A vulnerability labeled as critical has been found in Mattermost up to 10.11.19/11.6.4/11.7.2/11.7.x. Affected is an unknown function of the component Channel Patch API. Executing a manipulation can lead to improper synchronization. This vulnerability is handled as CVE-2026-10085. The attack can be executed remotely. There is not any exploit available.

Detailsinfo

A vulnerability was found in Mattermost up to 10.11.19/11.6.4/11.7.2/11.7.x. It has been declared as critical. This vulnerability affects an unknown part of the component Channel Patch API. The manipulation with an unknown input leads to a improper synchronization vulnerability. The CWE definition for the vulnerability is CWE-662. The product utilizes multiple threads or processes to allow temporary access to a shared resource that can only be exclusive to one process at a time, but it does not properly synchronize these actions, which might cause simultaneous accesses of this resource by multiple threads or processes. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to restrict the group_constrained channel flag to public and private channels that support group synchronization, which allows an ordinary group or direct message member to remove all participants from the conversation via the channel patch API.. Mattermost Advisory ID: MMSA-2026-00688

The advisory is available at mattermost.com. This vulnerability was named CVE-2026-10085 since 05/29/2026. The exploitation appears to be easy. The attack can be initiated remotely. The technical details are unknown and an exploit is not available.

Upgrading to version 10.11.20, 11.6.5, 11.7.3 or 11.8.0 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
• 11.0
• 11.1
• 11.2
• 11.3
• 11.4
• 11.5
• 11.6
• 11.6.0
• 11.6.1
• 11.6.2
• 11.6.3
• 11.6.4
• 11.7
• 11.7.0
• 11.7.1
• 11.7.2

License

• open-source

CPE 2.3info

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CPE 2.2info

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