Mattermost up to 11.7.10/11.8.5/11.9.1/11.10.1 Server Log information disclosure

Summaryinfo

A vulnerability classified as problematic has been found in Mattermost up to 11.7.10/11.8.5/11.9.1/11.10.1. This affects an unknown part of the component Server Log. Performing a manipulation results in information disclosure. This vulnerability was named CVE-2026-19600. The attack may be initiated remotely. There is no available exploit. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, was found in Mattermost up to 11.7.10/11.8.5/11.9.1/11.10.1. This affects some unknown processing of the component Server Log. The manipulation with an unknown input leads to a information disclosure vulnerability. CWE is classifying the issue as CWE-200. The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. This is going to have an impact on confidentiality. The summary by CVE is:

Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 fail to sanitize authentication tokens before writing them to server log entries, which allows an attacker with access to server logs to obtain valid session tokens or OAuth access tokens and impersonate authenticated users via the debug-level Mattermost server log.. Mattermost Advisory ID: MMSA-2026-00763

It is possible to read the advisory at mattermost.com. This vulnerability is uniquely identified as CVE-2026-19600 since 08/12/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. Additional levels of successful authentication are necessary for exploitation. It demands that the victim is doing some kind of user interaction. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1592 according to MITRE ATT&CK.

Upgrading to version 11.7.11, 11.8.6, 11.9.2, 11.10.2 or 11.11.0 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at CERT Bund (WID-SEC-2026-4009). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Affected

• Mattermost Mattermost

Productinfo

Type

• Groupware Software

Name

• Mattermost

Version

• 11.7.0
• 11.7.1
• 11.7.2
• 11.7.3
• 11.7.4
• 11.7.5
• 11.7.6
• 11.7.7
• 11.7.8
• 11.7.9
• 11.7.10
• 11.8.0
• 11.8.1
• 11.8.2
• 11.8.3
• 11.8.4
• 11.8.5
• 11.9.0
• 11.9.1
• 11.10.0
• 11.10.1

License

• open-source

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

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Entryinfo

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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