5.3

CVE-2026-10556

Unauthenticated webhook request with null notification entry could crash the Microsoft Calendar plugin.

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 null entries in Microsoft Graph webhook notification payloads, which allows an unauthenticated attacker to crash the Microsoft Calendar plugin process and deny calendar integration service to all users on the instance via a crafted {{POST}} request to the public webhook endpoint.. Mattermost Advisory ID: MMSA-2026-00693
Daten sind bereitgestellt durch National Vulnerability Database (NVD)
Mattermost ≫ Mattermost Server Version >= 10.11.0 < 10.11.23
Mattermost ≫ Mattermost Server Version >= 11.7.0 < 11.7.8
Mattermost ≫ Mattermost Server Version >= 11.8.0 < 11.8.5
Mattermost ≫ Mattermost Server Version >= 11.9.0 < 11.9.1
VulnDex Vulnerability Enrichment
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Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.25% 0.162
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
responsibledisclosure@mattermost.com 5.3 3.9 1.4
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CWE-476 NULL Pointer Dereference

The product dereferences a pointer that it expects to be valid but is NULL.

CWE-754 Improper Check for Unusual or Exceptional Conditions

The product does not check or incorrectly checks for unusual or exceptional conditions that are not expected to occur frequently during day to day operation of the product.

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