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TI-2026-08433 Aliases CVE-2026-9602GHSA-82vr-gjvh-q9r8

Mattermost Desktop App crashes when malformed arguments are provided to some exposed IPC methods

Priority LOW 26CWE-400Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-400.

Summary

Mattermost Desktop App versions <=6.2 6.0.2 5.6.13.0 fail to validate payloads sent from the Mattermost Web App to the Desktop App which allows a malicious server owner to crash the Mattermost Desktop App via changing the payload of a method to a malformed one. Mattermost Advisory ID: MMSA-2026-00678

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.0042 36th percentileScored 2026-11-07
Fix Fixed Mattermost (Mattermost): 6.3.0, 6.2.1.0, 5.13.7.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
MattermostMattermostup to 6.0.2; up to 5.6.136.3.0, 6.2.1.0, 5.13.7.0Patch availableCNA
  • Mattermost VendorMattermost Affected up to 6.0.2; up to 5.6.13 Fixed in 6.3.0, 6.2.1.0, 5.13.7.0 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:mattermost:mattermost_desktop:*:*:*:*:*:*:*:*before 5.13.7; 6.0.0 – 6.0.2; 6.2.0 to before 6.2.1VulnerableMattermost
  • cpe:2.3:a:mattermost:mattermost_desktop:*:*:*:*:*:*:*:* Versions before 5.13.7; 6.0.0 – 6.0.2; 6.2.0 to before 6.2.1 Vulnerable ·Mattermost

Remediation

  • Fix · CNA Mattermost (Mattermost) Fixed in 6.3.0, 6.2.1.0, 5.13.7.0

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-9602
  2. 2026-10-03 Alias added: GHSA-82vr-gjvh-q9r8

References

Advisory 1

  • TI-2019-15074 An issue was discovered in Mattermost Desktop App before 4.3.0 on macOS. CVSS 3.1CRITICAL 9.8
  • TI-2016-09099 An issue was discovered in Mattermost Desktop App before 3.4.0. CVSS 3.1CRITICAL 9.8
  • TI-2019-15079 An issue was discovered in Mattermost Desktop App before 4.2.2. CVSS 3.1HIGH 8.8
  • TI-2024-26542 RCE in desktop app in Windows by local attacker CVSS 3.1HIGH 7.8
  • TI-2026-05712 Mattermost Desktop App fails to restrict the allow list of domains which NTLM credentials are passed CVSS 3.1HIGH 7.7
  • TI-2026-00781 Arbitrary application execution via unvalidated server-controlled URLs in Help menu CVSS 3.1HIGH 7.6
See all 33 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences