CVE-2025-1398 - Mattermost Desktop <=5.10. macOS Entitlement Vulnerability

On June 5, 2024, a new vulnerability identified as CVE-2025-1398 was published, affecting the Mattermost Desktop App for macOS, specifically versions 5.10. and below. In simple terms, this bug means that anyone who gains remote access can use certain unused permissions (called “entitlements”) granted by the app to inject code into the system. This lets them bypass macOS’s privacy controls—Transparency, Consent, and Control (TCC)—which most Mac users count on to keep applications in check.

Let’s break down how it works, what it means, and how an attacker could exploit it.

What’s the Vulnerability About?

When you install an app on macOS, it asks for entitlements—special permissions that Apple uses to keep things locked down. For example, a web browser might need permission to use the camera or microphone. The Mattermost Desktop App version 5.10. and earlier versions granted itself extra permissions that it didn’t actually use.

If the app includes entitlements it doesn’t need (like com.apple.security.device.camera, or even more sensitive ones), it sort of leaves the door unlocked. Attackers who get remote access (over the internet or through some remote tool) can take advantage of these entitlements and inject malicious code into the app. This code then has privileges to bypass macOS privacy prompts and protections—called TCC.

What is TCC?

Apple’s Transparency, Consent, and Control (TCC) framework is what makes sure apps have to ask for your permission to access things like:

Photos

If an app has unnecessary entitlements, malware can sneak in and use these features without you ever knowing!

How Did This Happen?

The developer of Mattermost Desktop App explicitly declared several entitlements in the entitlements file when signing the app. Some were not needed for regular app features, and gave the process more power than it should have.

Here’s a simplified view of what might be in the app’s entitlements file (for illustration)

<!-- This is a snippet of an entitlements.plist file -->
<key>com.apple.security.device.camera</key>
<true/>
<key>com.apple.security.device.microphone</key>
<true/>
<key>com.apple.security.cs.allow-jit</key>
<true/>
<!-- Possibly more entitlements, even if unused! -->

With entitlements like com.apple.security.cs.allow-jit (allows just-in-time code execution) and device permissions, if an attacker gets code running in the app’s context (through remote access or vulnerability), they don’t need to ask you for permission to access these features—they already have it!

Step 1: Gain Remote Access

First, an attacker needs access—this usually comes from a different vulnerability, phishing, or malware.

Step 2: Inject Code

Once inside, they can inject malicious code into the Mattermost Desktop App process, using tools like DYLD_INSERT_LIBRARIES or other code injection techniques.

Here’s an example in bash to demonstrate code injection (educational, do not use for harm)

DYLD_INSERT_LIBRARIES=./malicious.dylib /Applications/Mattermost.app/Contents/MacOS/Mattermost

This runs the Mattermost app with a custom dynamic library injected, letting the injected code run with the same entitlements as the Mattermost app.

Now, the attacker has a process that can

- Capture webcam/microphone without prompting the user

Access user data intended to be protected by TCC

Here’s a simple Objective-C snippet that could be used in a malicious dylib to activate the microphone:

#import <AVFoundation/AVFoundation.h>
AVAudioRecorder *recorder = [[AVAudioRecorder alloc] init];
[recorder record];
// Audio is being recorded in the background, user receives no prompt.

Is There a Patch?

According to the official Mattermost security release page, this issue is fixed in version 5.10.1 and later. If you’re running Mattermost Desktop on a Mac, update now!

Upgrade/download: https://mattermost.com/download/#mattermost-apps

References

- CVE Page on NVD
- Mattermost Security Updates
- Apple TCC Technical Overview
- Introduction to macOS Entitlements

Update immediately – If you use Mattermost Desktop App v5.10. or below, upgrade now.

2. Audit app entitlements – If you’re an IT admin, review which apps have what entitlements on your fleet.

Conclusion

CVE-2025-1398 is a strong reminder: even well-meaning apps can make mistakes with permissions. Declaring unnecessary entitlements is giving attackers “keys to the house.” Always keep apps updated, and check for least privilege in software deployments.

If you want the technical details or need help checking your Mac for vulnerable apps, feel free to ask in the comments or review the official references above!

Timeline

Published on: 03/17/2025 15:15:43 UTC
Last modified on: 03/31/2025 16:15:22 UTC