CVE-2026-6346
Mattermost Support Packet Credential Exposure
Publication date: 2026-05-18
Last updated on: 2026-05-18
Assigner: Mattermost, Inc.
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| mattermost | mattermost_server | From 10.11.0 (inc) to 10.11.14 (exc) |
| mattermost | mattermost_server | From 11.4.0 (inc) to 11.4.4 (exc) |
| mattermost | mattermost_server | From 11.5.0 (inc) to 11.5.2 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-200 | The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. |
Attack-Flow Graph
AI Powered Q&A
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
The vulnerability allows a Mattermost System Admin or any party with access to a support packet to obtain sensitive credentials in plaintext. This exposure of sensitive information could potentially lead to non-compliance with data protection standards and regulations such as GDPR and HIPAA, which require the protection of sensitive data and credentials.
Since sensitive configuration fields are not sanitized before inclusion in support packets, unauthorized disclosure of credentials may occur, increasing the risk of data breaches and violating confidentiality requirements mandated by these regulations.
Can you explain this vulnerability to me?
This vulnerability affects certain versions of Mattermost (11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3) where sensitive configuration fields are not properly sanitized before being included in support packet generation.
As a result, a Mattermost System Admin or anyone with access to a support packet can obtain sensitive credentials in plaintext by downloading a support packet from the System Console.
How can this vulnerability impact me? :
This vulnerability can lead to the exposure of sensitive credentials in plaintext to unauthorized parties who have access to support packets.
Such exposure can compromise the confidentiality and integrity of the Mattermost system, potentially allowing attackers to escalate privileges or access sensitive data.
The CVSS score of 8.7 indicates a high severity impact, with high confidentiality and integrity impact but no impact on availability.
What immediate steps should I take to mitigate this vulnerability?
To mitigate this vulnerability, you should upgrade Mattermost to a version later than 11.5.1 for the 11.5.x series, later than 10.11.13 for the 10.11.x series, or later than 11.4.3 for the 11.4.x series, as these versions fix the issue of sensitive configuration fields not being sanitized in support packets.
Additionally, restrict access to support packets and the System Console to trusted administrators only, to prevent unauthorized access to sensitive credentials.