CVE-2026-1628— Mattermost allows external websites to open within the app, exposing preload functionality to non-trusted sites.
Quick assessment
Affected
Mattermost Mattermost
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
Mattermost Desktop App是美国Mattermost公司的一款消息传递桌面版应用程序。 Mattermost Desktop App 5.13.3及之前版本存在安全漏洞，该漏洞源于未附加限制导航到外部站点的监听器，可能导致恶意服务器向不受信任的服务器暴露预加载脚本功能。
Possible ATT&CK Techniques 1 AI
T1059 · Command and Scripting Interpreter
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I. Basic Information for CVE-2026-1628
Vulnerability Information
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Vulnerability Title
Mattermost allows external websites to open within the app, exposing preload functionality to non-trusted sites.
Source: CVE Program / CVE List V5
Vulnerability 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
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
从非可信控制范围包含功能例程
Source: CVE Program / CVE List V5
Vulnerability Title
Mattermost Desktop App 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Mattermost Desktop App是美国Mattermost公司的一款消息传递桌面版应用程序。 Mattermost Desktop App 5.13.3及之前版本存在安全漏洞，该漏洞源于未附加限制导航到外部站点的监听器，可能导致恶意服务器向不受信任的服务器暴露预加载脚本功能。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| Mattermost | Mattermost | 0 ~ 5.13.3 | - |
|
II. Public POCs for CVE-2026-1628
| # | POC Description | Source Link | Shenlong Link |
|---|
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Same weakness: CWE-829
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V. Comments for CVE-2026-1628
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