InfoSecBulletin Cybersecurity for mankind
The spoofing vulnerability, CVE-2025-30401, impacts all WhatsApp Desktop versions for Windows before 2.2450.6, posing a risk to users dealing with attachments on the platform.
According to the official security advisory, the application “displayed attachments according to their MIME type but selected the file opening handler based on the attachment’s filename extension.”
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This discrepancy created a dangerous loophole for malicious actors. When a user receives a WhatsApp attachment, the app shows the file type based on its MIME type (e.g., as an image), while the operating system opens the file based on its extension (e.g., .exe).
An attacker can create a file with a misleading MIME type and filename extension, tricking users into unintentionally running harmful code when they open what seems to be a safe attachment.
WhatsApp for Windows Vulnerability:
The attack is alarming because it exploits user trust. A cybercriminal could send a seemingly normal image file on WhatsApp, but it may actually be an executable file.
Opening this attachment in WhatsApp can lead to executing harmful code instead of viewing an image.
“A maliciously crafted mismatch could have caused the recipient to inadvertently execute arbitrary code rather than view the attachment when manually opening the attachment inside WhatsApp,” stated the official advisory from Facebook, WhatsApp’s parent company.
The summary of the vulnerability is given below:
Impact & Affected Versions:
The vulnerability impacts all versions of WhatsApp Desktop for Windows starting from version 0.0.0 up to but not including 2.2450.6.
CVE-2025-30401 has a high severity rating because it may allow remote code execution, potentially leading to unauthorized access or data theft.
Security analysts warn that this vulnerability is especially risky in group chats, as harmful attachments can affect multiple victims at once.
Messaging platforms have faced security issues before. In 2024, researcher Saumyajeet Das found a vulnerability in WhatsApp for Windows that allowed Python and PHP scripts to run without warning.
Users should update WhatsApp for Windows to version 2.2450.6 or later to fix the spoofing vulnerability.
