CVE-2026-3109

Mattermost Plugins versions <=11.4 10.11.11.0 fail to validate webhook request timestamps which allows an attacker to corrupt Zoom meeting state in Mattermost via replayed webhook requests. Mattermost Advisory ID: MMSA-2026-00584

CVSS v3 2.2 LOW

2.2^/10

CVSS v3 : LOW

Vector :

Exploitability : 0.7 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required HIGH

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact LOW

Scope UNCHANGED

References

Link	Resource
https://mattermost.com/security-updates	Vendor Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*

History

08 Jun 2026, 12:24

Type	Values Removed	Values Added
First Time		Mattermost mattermost Server Mattermost
References	~~() https://mattermost.com/security-updates -~~	() https://mattermost.com/security-updates - Vendor Advisory
CPE		cpe:2.3:a:mattermost:mattermost_server::::::::

30 Mar 2026, 13:26

Type	Values Removed	Values Added
Summary		(es) Las versiones <=11.4 10.11.11.0 de los plugins de Mattermost no validan las marcas de tiempo de las solicitudes de webhook, lo que permite a un atacante corromper el estado de las reuniones de Zoom en Mattermost mediante solicitudes de webhook repetidas. ID de aviso de Mattermost: MMSA-2026-00584

26 Mar 2026, 17:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-03-26 17:16

Updated : 2026-06-17 10:43

NVD link : CVE-2026-3109

Mitre link : CVE-2026-3109

CVE.ORG link : CVE-2026-3109

JSON object : View

Products Affected

mattermost

mattermost_server

CWE

CWE-754

Improper Check for Unusual or Exceptional Conditions

{"id": "CVE-2026-3109", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-3109", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-03-26T17:44:18.070716Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "responsibledisclosure@mattermost.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 2.2, "attackVector": "NETWORK", "baseSeverity": "LOW", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "HIGH", "availabilityImpact": "LOW", "privilegesRequired": "HIGH", "confidentialityImpact": "NONE"}, "impactScore": 1.4, "exploitabilityScore": 0.7}]}, "affected": [{"source": "responsibledisclosure@mattermost.com", "affectedData": [{"vendor": "Mattermost", "product": "Mattermost", "versions": [{"status": "affected", "version": "0", "versionType": "semver", "lessThanOrEqual": "10.11.11"}, {"status": "unaffected", "version": "11.5.0"}, {"status": "unaffected", "version": "10.11.12"}], "defaultStatus": "unaffected"}]}], "published": "2026-03-26T17:16:41.967", "references": [{"url": "https://mattermost.com/security-updates", "tags": ["Vendor Advisory"], "source": "responsibledisclosure@mattermost.com"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "responsibledisclosure@mattermost.com", "description": [{"lang": "en", "value": "CWE-754"}]}], "descriptions": [{"lang": "en", "value": "Mattermost Plugins versions <=11.4 10.11.11.0 fail to validate webhook request timestamps which allows an attacker to corrupt Zoom meeting state in Mattermost via replayed webhook requests. Mattermost Advisory ID: MMSA-2026-00584"}, {"lang": "es", "value": "Las versiones <=11.4 10.11.11.0 de los plugins de Mattermost no validan las marcas de tiempo de las solicitudes de webhook, lo que permite a un atacante corromper el estado de las reuniones de Zoom en Mattermost mediante solicitudes de webhook repetidas. ID de aviso de Mattermost: MMSA-2026-00584"}], "lastModified": "2026-06-17T10:43:03.587", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "D144BD1D-F65C-498D-BC8A-F3D718F47F4B", "versionEndExcluding": "10.11.12", "versionStartIncluding": "10.11.0"}], "operator": "OR"}]}], "sourceIdentifier": "responsibledisclosure@mattermost.com"}