CVE-2024-37182: Mattermost Desktop App RCE Vulnerability

CVE-2024-37182 Overview

CVE-2024-37182 affects Mattermost Desktop App versions 5.7.0 and earlier. The application fails to correctly prompt users for permission when opening external URLs. A remote attacker can force a victim to execute arbitrary programs on the local system through custom URI schemes. Exploitation requires user interaction, such as clicking a crafted link delivered over the Internet. The flaw is classified under [CWE-693] Protection Mechanism Failure.

Critical Impact

Remote attackers can trigger arbitrary program execution on a victim's workstation by abusing custom URI schemes, bypassing the expected permission prompt in the Mattermost Desktop App.

Affected Products

• Mattermost Desktop App versions <= 5.7.0
• Windows, macOS, and Linux desktop clients built on the affected release line
• Deployments where users receive external messages or links through Mattermost channels

Discovery Timeline

• 2024-06-14 - CVE-2024-37182 published to the National Vulnerability Database
• 2026-06-17 - Last updated in NVD database

Technical Details for CVE-2024-37182

Vulnerability Analysis

The Mattermost Desktop App is an Electron-based client that renders chat content and handles outbound navigation to external resources. The permission dialog that should intercept external URL activation is not applied consistently to custom URI schemes. An attacker who posts or sends a crafted link can cause the client to pass the URI directly to the operating system handler. Registered schemes on the victim's host can then launch native applications with attacker-controlled arguments. The result is arbitrary program execution scoped to whatever handlers exist on the endpoint.

Root Cause

The root cause is a missing or incorrectly enforced protection mechanism around external URL handling [CWE-693]. The client distinguishes between standard web protocols and custom schemes but does not uniformly route all external targets through the user consent prompt. Custom schemes registered by other installed software reach the OS shell handler without warning.

Attack Vector

Exploitation occurs over the network and requires user interaction, consistent with the scope change in the CVSS vector. An attacker sends a message, invitation, or shared link containing a malicious custom URI. When the victim clicks the link inside the Mattermost Desktop App, the OS invokes the registered handler for that scheme. Depending on installed applications, this can launch binaries, open installers, or execute scripts with the user's privileges. No authentication to the target Mattermost server is required beyond the ability to deliver content the victim will click.

No verified public proof-of-concept is available at the time of writing. Refer to the Mattermost Security Updates page for vendor technical details.

Detection Methods for CVE-2024-37182

Indicators of Compromise

• Mattermost Desktop App process (Mattermost.exe, Mattermost) spawning unexpected child processes such as cmd.exe, powershell.exe, wscript.exe, or installer binaries
• Chat messages or channel posts containing links with uncommon URI schemes (for example ms-cxh:, search-ms:, javaws:, or vendor-specific handlers)
• Shell handler invocations originating from the Mattermost renderer immediately after a user click event

Detection Strategies

• Hunt for process lineage where the Mattermost Desktop binary is the parent of interpreter or scripting hosts
• Correlate endpoint telemetry with proxy or DNS logs showing links to attacker-controlled infrastructure immediately preceding the child process spawn
• Review installed URI scheme handlers on managed workstations and flag high-risk schemes that can execute code

Monitoring Recommendations

• Enable command-line auditing on Windows (Audit Process Creation with command line) and execve auditing on Linux endpoints
• Alert on new or modified registry entries under HKCR\ on Windows that register URI scheme handlers
• Track Mattermost Desktop App version inventory and flag endpoints running 5.7.0 or earlier

How to Mitigate CVE-2024-37182

Immediate Actions Required

• Upgrade the Mattermost Desktop App to a version later than 5.7.0 on all managed endpoints
• Inventory and remove the vulnerable client from systems that cannot be upgraded immediately
• Advise users to avoid clicking unfamiliar links inside Mattermost until patching is complete

Patch Information

Mattermost addressed the issue in Desktop App releases following 5.7.0. Review the Mattermost Security Updates advisory for the exact fixed version and release notes before deploying.

Workarounds

• Restrict or unregister high-risk custom URI scheme handlers on endpoints where they are not required for business use
• Apply application control policies that prevent the Mattermost Desktop App from spawning scripting hosts and installer utilities
• Use endpoint protection policies to block execution of untrusted binaries launched through URI handlers

# Example: list registered URI scheme handlers on Windows for review
reg query HKCR /s /f "URL Protocol" | findstr /i "URL Protocol"