CVE-2026-12284

Mattermost Desktop App Missing IPC Sender Validation in Calls Leave Handler

LOW
3.7
CVSS Score
Published: September 17, 2026 at 03:11 PM UTC
Updated: October 13, 2026 at 12:04 PM UTC
2 products affected across 1 vendorMattermost DesktopMattermost

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Severity
LOW3.7
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

Description

Mattermost Desktop App versions <=6.2 6.2.2.0 fails to validate the IPC sender in the leaveCall handler which allows a malicious or compromised Mattermost server (or a user with script access to a connected server view) to disconnect an active call belonging to a different connected server via the desktopAPI.leaveCall IPC message. Mattermost Advisory ID: MMSA-2026-00699

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

6.2.0 ≤ v < 6.2.3
0 ≤ v ≤ 6.2.2
Vendor states this is fixed in 6.2.3.0 (unaffected)
Vendor states this is fixed in 6.3.0 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (1)

Vendor Advisory
Source: cverecord
https://mattermost.com/security-updates

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
LOW
Vector?

Quick Info

StatusANALYZED
CWE
CWE-346

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