CVE-2026-1628

Mattermost allows external websites to open within the app, exposing preload functionality to non-trusted sites.

Published: Mar 2, 2026Updated: Mar 5, 2026 Sources: CVE List NVDCWE-829

4.6MEDIUM

Description

Mattermost Desktop App versions <=5.13.3 fail to attach listeners restricting navigation to external sites within the Mattermost app which allows a malicious server to expose preload script functionality to untrusted servers via having a user open an external link in their Mattermost server. Mattermost Advisory ID: MMSA-2026-00596

No summary for this CVE yet.

CVSS Vector Breakdown

Exploitability

AV:NAttack Vector

Network

AC:LAttack Complexity

Low

PR:LPrivileges Required

Low

UI:RUser Interaction

Required

Scope

S:UScope

Unchanged

Impact

C:LConfidentiality

Low

I:LIntegrity

Low

A:NAvailability

None

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Weaknesses

CWE-829

Affected Products

Mattermost

commercial·US

mattermost desktopOn-premDesktop App

Communications / messaging-chat

MattermostOn-premWeb App

Communications / messaging-chat

Exploitability

Official Patch Available

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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

1 technique

Initial Access

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References

https://mattermost.com/security-updates

mattermost.com

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