CVE-2025-21088— WebApp crash via improper validation of proto style in attachments
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公司的一个开源协作平台。 Mattermost存在代码问题漏洞，该漏洞源于未能正确验证提供给操作样式的proto样式，允许攻击者通过精心设计的恶意输入使前端崩溃。
Possible ATT&CK Techniques 1 AI
T1190 · Exploit Public-Facing Application
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I. Basic Information for CVE-2025-21088
Vulnerability Information
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Vulnerability Title
WebApp crash via improper validation of proto style in attachments
Source: CVE Program / CVE List V5
Vulnerability Description
Mattermost versions 10.2.x <= 10.2.0, 9.11.x <= 9.11.5, 10.0.x <= 10.0.3, 10.1.x <= 10.1.3 fail to properly validate the style of proto supplied to an action's style in post.props.attachments, which allows an attacker to crash the frontend via crafted malicious input.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
不正确的类型转换
Source: CVE Program / CVE List V5
Vulnerability Title
Mattermost 代码问题漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Mattermost是美国Mattermost公司的一个开源协作平台。 Mattermost存在代码问题漏洞，该漏洞源于未能正确验证提供给操作样式的proto样式，允许攻击者通过精心设计的恶意输入使前端崩溃。
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 | 10.2.0 | - |
|
II. Public POCs for CVE-2025-21088
| # | POC Description | Source Link | Shenlong Link |
|---|
AI-Generated POC
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Same Patch Batch · Mattermost · 2025-01-15 · 6 CVEs total
| CVE-2025-21083 | 6.5 MEDIUM | Insufficient Input Validation on Post Props |
| CVE-2025-20036 | 6.5 MEDIUM | Insufficient Input Validation on Post Props |
| CVE-2025-20086 | 6.5 MEDIUM | Insufficient Input Validation on Post Props |
| CVE-2025-20088 | 6.5 MEDIUM | Insufficient Input Validation on Post Props |
| CVE-2025-0476 | 4.3 MEDIUM | Mobile crash via file with specially crafted filename |
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V. Comments for CVE-2025-21088
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