WhatsApp for Windows Flaw Allowed Remote Code Execution via File Attachments

A critical vulnerability identified as CVE-2025-30401 was recently disclosed, highlighting a major security flaw in WhatsApp for Windows.

This issue, which primarily affects desktop application versions prior to 2.2450.6, allowed attackers to exploit mismatched file metadata to execute arbitrary code on unsuspecting users’ systems.

Technical Details of CVE-2025-30401

According to the Facebook blog, the vulnerability arises from a spoofing issue in how WhatsApp handles file attachments.

Specifically, WhatsApp for Windows displayed incoming attachments based on their MIME type (a descriptor of the file’s content), but it selected the file opening handler based on the attachment’s filename extension.

An attacker could exploit this mismatch to craft a file that appears harmless—such as a document or image file—but executes harmful code when opened.

For example, a malicious actor could send a file pretending to be a .jpeg image (based on its MIME type), but the file’s actual extension might be .exe.

If the victim manually opened the attachment inside WhatsApp, the system would execute the malicious file, enabling remote code execution (RCE).

Scope of Impact and Affected Versions

The vulnerability affected users of WhatsApp Desktop for Windows across all versions before 2.2450.6. Notably:

• Affected software: WhatsApp Desktop for Windows (Facebook).
• Unaffected by default: Users running later versions, such as 2.2450.6 or newer, are not impacted. Additionally, users who relied on WhatsApp for mobile or macOS were unaffected.

By exploiting this flaw, attackers could potentially execute arbitrary code on the victim’s device.

This could enable them to take full control of the system, steal sensitive information, or deploy additional malicious software.

The flaw required specific user interaction—namely, manually opening the attachment within the app—making targeted attacks more likely than indiscriminate campaigns.

Patch and Mitigation

WhatsApp acted swiftly upon discovering the flaw, releasing an updated version to address the vulnerability. 

Users are strongly encouraged to update their WhatsApp Desktop for Windows to version 2.2450.6 or later.

Furthermore, users are advised to:

• Avoid opening file attachments from untrusted or suspicious sources.
• Regularly update all software to stay protected from known vulnerabilities.

CVE-2025-30401 underscores the importance of vigilance in handling file attachments, even on trusted platforms.

While WhatsApp has patched this vulnerability, the incident serves as a reminder for users to stay proactive in their cybersecurity practices.

If you’re using WhatsApp Desktop for Windows, don’t delay—update your app today to safeguard your system.

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