Bug 2451785 (CVE-2026-3108)

Summary: CVE-2026-3108 Mattermost: mmctl: Mattermost mmctl: Administrator terminal manipulation via crafted messages
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Mattermost. This vulnerability in the `mmctl` command-line interface allows attackers to manipulate administrator terminals. By sending specially crafted messages containing ANSI and Operating System Command (OSC) escape sequences, an attacker can enable screen manipulation, display fake prompts, and hijack the administrator's clipboard, potentially exposing sensitive information or tricking administrators into executing malicious commands.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-03-26 17:02:29 UTC
Mattermost versions 11.2.x <= 11.2.2, 10.11.x <= 10.11.10, 11.4.x <= 11.4.0, 11.3.x <= 11.3.1 fail to sanitize user-controlled post content in the mmctl commands terminal output which allows attackers to manipulate administrator terminals via crafted messages containing ANSI and OSC escape sequences that enable screen manipulation, fake prompts, and clipboard hijacking.. Mattermost Advisory ID: MMSA-2026-00599