CVE-2026-8683— Overly long URLs crash the Mattermost Desktop App
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是美国Mattermost公司开源的一个开源协作平台。 Mattermost 5.5.13.0及之前版本存在资源管理错误漏洞，该漏洞源于未正确处理超长URL，可能导致恶意服务器所有者通过包含脚本调用window.open并传入超长URL使应用程序崩溃。
Possible ATT&CK Techniques 2 AI
T1059 · Command and Scripting Interpreter T1203 · Exploitation for Client ExecutionAffected Version Matrix 3
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| Mattermost | Mattermost | ≤ 5.5.13 |
affected |
6.2.0 |
unaffected | ||
5.13.6.0 |
unaffected |
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I. Basic Information for CVE-2026-8683
Vulnerability Information
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Vulnerability Title
Overly long URLs crash the Mattermost Desktop App
Source: CVE Program / CVE List V5
Vulnerability Description
Mattermost Desktop App versions <=6.1 5.5.13.0 fail to account for attempting to open extremely long URLs in the Mattermost Desktop App which allows a malicious server owner to crash the application via including a script to call window.open on a very large URL. Mattermost Advisory ID: MMSA-2026-00652
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
不加限制或调节的资源分配
Source: CVE Program / CVE List V5
Vulnerability Title
Mattermost 资源管理错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Mattermost是美国Mattermost公司开源的一个开源协作平台。 Mattermost 5.5.13.0及之前版本存在资源管理错误漏洞，该漏洞源于未正确处理超长URL，可能导致恶意服务器所有者通过包含脚本调用window.open并传入超长URL使应用程序崩溃。
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 ~ 5.5.13 | - |
|
II. Public POCs for CVE-2026-8683
| # | POC Description | Source Link | Shenlong Link |
|---|
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