CVE-2025-47957: Critical Use-After-Free Vulnerability in Microsoft Office Word

Overview

CVE-2025-47957 represents a significant vulnerability in Microsoft Office Word, a widely-used software application across organizations of all sizes globally. This vulnerability is categorized as a Use-After-Free flaw, which if exploited, permits an unauthorized attacker to execute code locally on the victim’s machine. Given the ubiquity of Microsoft Office Word, this vulnerability holds the potential to impact a vast number of systems, warranting immediate attention and mitigation from all users and administrators.

Vulnerability Summary

CVE ID: CVE-2025-47957
Severity: Critical (CVSS Severity Score: 8.4)
Attack Vector: Local
Privileges Required: Low
User Interaction: Required
Impact: System Compromise, Data Leakage

Affected Products

Product | Affected Versions

Microsoft Office Word | All versions prior to the vendor patch

How the Exploit Works

The exploit works by leveraging a Use-After-Free vulnerability present in Microsoft Office Word. This class of vulnerability arises when a program continues to use a pointer after it has been freed. An attacker can manipulate this flaw by crafting a malicious document that, when opened in Word, triggers the vulnerability and allows the attacker to execute code locally on the victim’s machine.

Conceptual Example Code

While the exact exploit code would be specific to the attacker, a conceptual example of how this vulnerability might be exploited could look like this:

#include <windows.h>
// The malicious payload
void payload() {
//...
}
// The function to trigger the use-after-free vulnerability
void trigger_vulnerability() {
char* ptr = (char*) malloc(100);
strcpy(ptr, "sensitive data");
free(ptr);
// Use after free
strcpy(ptr, payload);
}
int main() {
trigger_vulnerability();
return 0;
}

In this simplified conceptual example, the `trigger_vulnerability` function first allocates memory (`ptr`), then frees it, and finally attempts to use it again to store the malicious payload. This results in undefined behavior, which an attacker can potentially leverage to execute their malicious payload.

Mitigation and Remediation

The primary mitigation strategy for CVE-2025-47957 is to apply the vendor-provided patch. Microsoft has released a patch that resolves this vulnerability, and it is strongly recommended that all users and system administrators download and install this patch as soon as possible.
In instances where patching is not immediately feasible, temporary mitigation can be achieved through the use of Web Application Firewalls (WAFs) or Intrusion Detection Systems (IDS). These tools can help detect and block attempts to exploit this vulnerability, providing a layer of protection while a more permanent solution is implemented.