Author: Ameeba

Overview

CVE-2025-54906 is a significant vulnerability that affects Microsoft Office, a widely used productivity suite. This vulnerability arises from flawed memory management, specifically the freeing of memory not on the heap, which potentially allows an unauthorized attacker to execute code locally. Due to the broad usage of Microsoft Office, this vulnerability could have a substantial impact on organizations across the globe, highlighting the necessity for immediate attention and mitigation.

Vulnerability Summary

CVE ID: CVE-2025-54906
Severity: High (CVSS: 7.8)
Attack Vector: Local
Privileges Required: None
User Interaction: Required
Impact: Potential system compromise or data leakage

Affected Products

Product | Affected Versions

Microsoft Office | All versions prior to the vendor patch

How the Exploit Works

The vulnerability lies in the incorrect handling of memory not on the heap within Microsoft Office. An attacker could craft a malicious file that, when opened in Microsoft Office, triggers the flaw and allows the attacker to execute arbitrary code on the victim’s system. This code execution occurs in the context of the current user.

Conceptual Example Code

This is a conceptual example, representing how a malicious payload might be embedded in a Microsoft Office file to exploit this vulnerability:

<doc>
<element attribute="exp">
<![CDATA[
function exploit() {
var malicious_code = "Base64 encoded malicious code";
var vulnerable_memory = freeHeapMemory();
vulnerable_memory.execute(malicious_code);
}
exploit();
]]>
</element>
</doc>

In this hypothetical example, the malicious code is embedded within a function that is called when the document is opened. The `freeHeapMemory` function call triggers the vulnerability, allowing the execution of the malicious code as the current user.

Overview

CVE-2025-54904 is a significant cybersecurity vulnerability detected in Microsoft Office Excel software. This vulnerability presents a serious risk to users worldwide as it allows an unauthorized attacker to execute code locally, potentially leading to system compromise or data leakage. The risk is particularly severe due to the widespread use of Microsoft Office Excel across diverse sectors, including businesses, education, and government.

Vulnerability Summary

CVE ID: CVE-2025-54904
Severity: High (7.8 CVSS Score)
Attack Vector: Local
Privileges Required: None
User Interaction: Required
Impact: System compromise or data leakage

Affected Products

Product | Affected Versions

Microsoft Office Excel | All versions prior to the security patch

How the Exploit Works

The exploit takes advantage of a ‘use after free’ vulnerability in Microsoft Office Excel. This involves the attacker crafting a specially designed Excel file that, when opened by the victim, manipulates the memory allocation within the application. The attacker can then execute arbitrary code in the context of the current user. If the user possesses administrative rights, the attacker could potentially gain control over the affected system.

Conceptual Example Code

The following pseudocode demonstrates a conceptual example of how the vulnerability might be exploited. Note that this is a simplified representation and actual exploitation would require a more sophisticated understanding of Excel’s memory management and the target system’s architecture.

create malicious_excel_file
open malicious_excel_file in Microsoft Office Excel
// The following is the malicious payload
free(memory_block)
write_to_memory_block(arbitrary_code)
execute(memory_block)
close malicious_excel_file

This pseudocode demonstrates the high-level process of exploiting the use-after-free vulnerability. The attacker creates a malicious Excel file that, when opened, frees a block of memory. It then writes arbitrary code to the same memory block and executes that code.

Overview

A severe vulnerability has been identified in Microsoft Office Excel, a widely used spreadsheet tool, that could allow an unauthorized attacker to execute code on the victim’s system. Given the extensive use of Microsoft Office Excel in both personal and corporate environments, the potential impact of this vulnerability is significant.

Vulnerability Summary

CVE ID: CVE-2025-54903
Severity: High (CVSS: 7.8)
Attack Vector: Local
Privileges Required: None
User Interaction: Required
Impact: Potential system compromise and data leakage

Affected Products

Product | Affected Versions

Microsoft Office Excel | All versions prior to the latest patch

How the Exploit Works

The vulnerability stems from a “use after free” flaw in Microsoft Office Excel. In essence, this means that the software continues to use memory after it has been freed or deleted. This can lead to undefined behavior, including the execution of arbitrary code, which an attacker could potentially use to take control of the affected system or access sensitive data.

Conceptual Example Code

To exploit this vulnerability, an attacker might craft a malicious Excel document that triggers the “use after free” flaw when opened. The following pseudocode provides a conceptual example:

# Pseudocode
class MaliciousDocument:
def __init__(self):
self.trigger = None
def open(self):
self.trigger = allocate_memory()
self.trigger.use_after_free()
malicious_doc = MaliciousDocument()
malicious_doc.open()

In this example, `use_after_free()` represents the flawed function in Excel that leads to the vulnerability. The attacker would replace this with actual malicious code to exploit the vulnerability.

Mitigation and Countermeasures

Users can protect themselves from this vulnerability by applying the latest patch from Microsoft. In the absence of a patch, using a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can provide temporary mitigation. However, these are not long-term solutions and cannot fully protect against the vulnerability, so applying the patch as soon as it is available is strongly recommended.

Overview

The CVE-2025-54902 vulnerability is a dangerous flaw found in Microsoft Office Excel. It allows an unauthorized attacker to execute code locally through an out-of-bounds read. This vulnerability can lead to potential system compromise or data leakage, making it a significant threat to any organization using the affected versions of Microsoft Office Excel.

Vulnerability Summary

CVE ID: CVE-2025-54902
Severity: High (7.8 CVSS)
Attack Vector: Local
Privileges Required: None
User Interaction: Required
Impact: Potential system compromise and data leakage

Affected Products

Product | Affected Versions

Microsoft Office Excel | All versions before the latest patch

How the Exploit Works

The exploit works by taking advantage of an out-of-bounds read error in Microsoft Office Excel. The attacker sends a specially crafted file to the victim, who opens it using the vulnerable Excel software. This allows the attacker to read data they’re not supposed to have access to or execute arbitrary code on the victim’s system.

Conceptual Example Code

The following is a
conceptual
example of how this vulnerability might be exploited. The attacker would craft a malicious Excel file with an embedded payload designed to trigger the out-of-bounds read.

# Generate malicious Excel file
$ msfvenom -p windows/exec CMD=calc.exe -f xls > malicious.xls
# Send the malicious file to the victim
$ mail -a malicious.xls -s "Important Document" victim@example.com

In this example, the `msfvenom` command is used to generate a malicious Excel file that, when opened, would execute the `calc.exe` program on the victim’s machine. The malicious file is then sent to the victim via email. When the victim opens the file, the payload is executed, exploiting the vulnerability.
Please note that this is a hypothetical example and is not meant to encourage malicious activities. It is intended to illustrate how such a vulnerability could be exploited.

Overview

The vulnerability, identified as CVE-2025-54899, pertains to Microsoft Office Excel’s flaw in memory management, which allows for unauthorized local code execution. This critical vulnerability affects all users of the said software and poses a significant threat due to the potential for system compromise or data leakage if exploited.

Vulnerability Summary

CVE ID: CVE-2025-54899
Severity: High (7.8 CVSS Score)
Attack Vector: Local
Privileges Required: None
User Interaction: Required
Impact: Potential system compromise and data leakage

Affected Products

Product | Affected Versions

Microsoft Office Excel | All versions prior to patch

How the Exploit Works

The vulnerability stems from an error in Excel’s memory management, specifically in the freeing of memory not on the heap. An attacker can exploit this flaw by inducing a condition wherein Excel attempts to free memory that was not allocated on the heap. This could allow the attacker to execute arbitrary code on the victim’s system, leading to a potential system compromise or data leakage.

Conceptual Example Code

Given the nature of the vulnerability, an example exploit could involve a specially crafted Excel file that, when opened, triggers the memory mismanagement issue and executes arbitrary code. Conceptually, this could look like:

Sub Workbook_Open()
' Malicious payload that triggers memory mismanagement
Dim buffer As String
buffer = String(1000000, "A")
End Sub

In this conceptual example, the malicious Excel file contains VBA code that is automatically executed when the file is opened. The code attempts to allocate an excessively large amount of memory, simulating a condition that could lead to the vulnerability being exploited. Note that this is a simplified example and actual exploitation would likely involve more complex techniques.

Overview

This report addresses the critical vulnerability, CVE-2025-54898, a serious out-of-bounds read flaw found in Microsoft Office Excel. This vulnerability, if exploited, could allow an unauthorized attacker to execute arbitrary code on the target system. Considering the wide usage of Microsoft Office Excel across various sectors, such a vulnerability could have significant implications, potentially leading to a compromise of systems or leakage of confidential data.

Vulnerability Summary

CVE ID: CVE-2025-54898
Severity: High (CVSS: 7.8)
Attack Vector: Local
Privileges Required: None
User Interaction: Required
Impact: Potential system compromise or data leakage

Affected Products

Product | Affected Versions

Microsoft Office Excel | All versions until patched

How the Exploit Works

The vulnerability is an out-of-bounds read error within Microsoft Office Excel. This occurs when the application attempts to read data that is outside the intended boundary of a buffer. An attacker could craft a malicious Excel file that, when opened by the user, exploits this vulnerability to execute arbitrary code. This code execution occurs in the context of the current user and could lead to a complete compromise of the affected system.

Conceptual Example Code

The following is a conceptual example of how the vulnerability might be exploited via a malicious Excel file:

POST /upload_file HTTP/1.1
Host: target.example.com
Content-Type: application/vnd.ms-excel
{ "file": "<base64_encoded_malicious_excel_file>" }

Please note that this is a simplified example and the actual exploit would involve crafting a specific Excel file to trigger the out-of-bounds read.

Recommendations

To mitigate this vulnerability, users are advised to apply the latest vendor patch provided by Microsoft. In the absence of a patch, a Web Application Firewall (WAF) or Intrusion Detection System (IDS) could serve as temporary mitigation methods. However, these are not foolproof and can only serve to detect or prevent known exploitation techniques. Therefore, the application of the vendor patch remains the most effective mitigation strategy.

Overview

The vulnerability, identified as CVE-2025-54896, is a severe security risk present in Microsoft Office Excel. It allows an unauthorized attacker to execute code locally on the affected system, potentially leading to system compromise or sensitive data leakage. Given the widespread use of Microsoft Office Excel in both personal and professional environments, this vulnerability poses a significant threat to countless users worldwide.

Vulnerability Summary

CVE ID: CVE-2025-54896
Severity: High (7.8 CVSS score)
Attack Vector: Local
Privileges Required: None
User Interaction: Required
Impact: System compromise and potential data leakage

Affected Products

Product | Affected Versions

Microsoft Office Excel | All versions prior to the latest patch

How the Exploit Works

This vulnerability exploits a flaw in the memory management of Microsoft Office Excel. The issue is due to a use-after-free condition in the software, which means the software uses memory space after it’s been freed. As a result, an attacker can input malicious code which can then be executed by the software, allowing unauthorized access and potentially compromising the system or leaking sensitive data.

Conceptual Example Code

Consider a scenario where the attacker sends a specially crafted Excel file to the victim. The file contains malicious code that is executed once the file is opened in a vulnerable version of Excel. The code could look something like this:

=CALL("Kernel32","VirtualAlloc","JJJJJ",0,1000,4096,64)
=CALL("Kernel32","RtlMoveMemory","JJJCJ",return_value,"[malicious_code]",100)
=CALL("Kernel32","CreateThread","JJJJJJJJ",0,0,return_value,0,0,0,0)
=RETURN()

This is just a conceptual example, the actual exploit may be more complex and context-specific.

Mitigation Guidance

Users are strongly advised to apply the latest vendor patch from Microsoft. In the absence of an immediate patch, using a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can provide temporary mitigation. Security teams should also consider implementing strict controls on the opening of Excel files from untrusted sources.