CVE-2026-8075 PUBLISHED

Posting a malicious markdown image crashes the Mattermost Desktop App

Assigner: Mattermost
Reserved: 07.05.2026 Published: 17.07.2026 Updated: 17.07.2026

Mattermost Desktop App versions <=6.2 5.5.13 6.0.2.0 fail to properly null check when checking for headers in the Mattermost Desktop App which allows any user to crash another channel members Desktop App via posting a malicious link with an embedded image that misses one of those headers. Mattermost Advisory ID: MMSA-2026-00668

Metrics

CVSS 3.1

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

Attack Vector	Network	Scope	Unchanged
Attack Complexity	Low	Confidentiality Impact	None
Privileges Required	Low	Integrity Impact	None
User Interaction	None	Availability Impact	High

CVSS 3.1

Product Status

Vendor	Mattermost
Product	Mattermost
Versions	Default: unaffected affected from 0 to 5.5.13 (incl.) affected from 0 to 6.0.2 (incl.) Version 6.3.0 is unaffected Version 5.13.6.0 is unaffected Version 6.2.1.0 is unaffected

Solutions

Update Mattermost Desktop App to versions 6.3.0, 5.13.6.0, 6.2.1.0 or higher.

Credits

Jopraveen finder

References

MMSA-2026-00668

Problem Types

CWE-754: Improper Check for Unusual or Exceptional Conditions CWE