CVE-2026-4915

MediumCVSS 6.5/10Last modified Jul 23, 2026

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

Metrics

CVSS 3.1 6.5/10CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness enumeration

CWE-754

Affected software

No affected versions have been published.

Timeline

Published
May 25, 2026
Last modified
Jul 23, 2026
NVD status
Analyzed

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CVE-2026-4915: Medium severity, CVSS 6.5 | Vulnix