CVE-2023-40703

Denial of Service via specially crafted block fields in Mattermost Boards

Published Nov 27, 2023 CVSS 3.1 · 4.3 Medium EPSS < 1% KEV · Not listed
Description
Mattermost fails to properly limit the characters allowed in different fields of a block in Mattermost Boards allowing a attacker to consume excessive resources, possibly leading to Denial of Service, by patching the field of a block using a specially crafted string. 

Remediation

Vendor Solution

Update Mattermost Server to versions 9.1.1, 9.0.2, 7.8.13, 8.1.4 or higher.

Tracking

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Advisories

Source ID Title
EUVD EUVD EUVD-2023-2945 Mattermost fails to properly limit the characters allowed in different fields of a block in Mattermost Boards allowing a attacker to consume excessive resources, possibly leading to Denial of Service, by patching the field of a block using a specially crafted string. 
Github GHSA Github GHSA GHSA-c37r-v8jx-7cv2 Mattermost Uncontrolled Resource Consumption vulnerability
References
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
Mattermost
Published
Updated
Jun 3, 2025, 2:01 PM
Reserved
Nov 22, 2023, 11:18 AM
Status
Modified
Published
Nov 27, 2023, 10:15 AM
Modified
Jun 17, 2026, 6:19 AM