CVE-2026-9602Network attack vector

Client crash via malformed IPC method arguments

Published Jul 17, 2026 · Updated Jul 17, 2026

Improper input validation in Mattermost Desktop App 6.0.2 and earlier allows remote authenticated users to crash the client. Exposed IPC methods process payloads from the Mattermost Web App without first validating each method's argument shape. A malicious server owner can substitute malformed method arguments, terminating the connected desktop application without reading or altering its data.

CVSS severity6.5
Medium
EPSS probability0.42%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in Mattermost Desktop App 6.0.2 and earlier allows remote authenticated users to crash the client. Exposed IPC methods process payloads from the Mattermost Web App without first validating each method's argument shape. A malicious server owner can substitute malformed method arguments, terminating the connected desktop application without reading or altering its data.

The record

CVE
CVE-2026-9602
Published
Jul 17, 2026
Updated
Jul 17, 2026
Vendor
Mattermost
Product
Mattermost
Classifications
CWE-400, T1499
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 17, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 17, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=5.6.13
  2. Affected versionversion=0 <=6.0.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Mattermost · Mattermostversion=0 <=5.6.13; version=0 <=6.0.2

Published CVSS scores

6.5Mattermost, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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