Server panic via outgoing webhook responses_CVE-2026-4915

6.5 / 10

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Description

Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to filter nil elements from outgoing webhook attachment payloads before processing, which allows an authenticated user to cause a denial of service (server process termination) via a crafted webhook callback response containing a null attachment entry.. Mattermost Advisory ID: MMSA-2026-00641

Basic Information

ID CVE-2026-4915

Source Mattermost

Published May 25, 2026 at 07:10

Affected Product

Vendor Mattermost

Product Mattermost

Version 11.6.0

Affected Versions Mattermost Mattermost 11.6.0
Mattermost Mattermost 11.5.0
Mattermost Mattermost 11.4.0
Mattermost Mattermost 10.11.0

CWE Classification

CWE-754

References

mattermost.com /security-updates

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    "published": "2026-05-25T07:10:23.254Z",
    "modified": "2026-05-25T07:10:23.254Z",
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