Mattermost service up to 10.11.10/11.2.2/11.3.0 Interactive Message memory allocation

Summaryinfo

A vulnerability was found in Mattermost service up to 10.11.10/11.2.2/11.3.0. It has been rated as problematic. This impacts an unknown function of the component Interactive Message Handler. The manipulation leads to memory allocation. This vulnerability is traded as CVE-2026-2456. It is possible to initiate the attack remotely. There is no exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in Mattermost service up to 10.11.10/11.2.2/11.3.0 and classified as problematic. This issue affects an unknown function of the component Interactive Message Handler. The manipulation with an unknown input leads to a memory allocation vulnerability. Using CWE to declare the problem leads to CWE-789. The product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated. Impacted is availability. The summary by CVE is:

Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 Mattermost fails to limit the size of responses from integration action endpoints, which allows an authenticated attacker to cause server memory exhaustion and denial of service via a malicious integration server that returns an arbitrarily large response when a user clicks an interactive message button.. Mattermost Advisory ID: MMSA-2026-00571

The weakness was shared by Daniel Espino Garcia. It is possible to read the advisory at mattermost.com. The identification of this vulnerability is CVE-2026-2456 since 02/13/2026. The exploitation is known to be difficult. The attack may be initiated remotely. It demands that the victim is doing some kind of user interaction. The technical details are unknown and an exploit is not publicly available.

Upgrading to version 10.11.11, 11.2.3, 11.3.1 or 11.4.0 eliminates this vulnerability.

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Productinfo

Type

• Groupware Software

Vendor

• Mattermost

Name

• service

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
• 11.0
• 11.1
• 11.2
• 11.2.0
• 11.2.1
• 11.2.2
• 11.3.0

License

• open-source

CPE 2.3info

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CPE 2.2info

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• 🔒
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Entryinfo

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