Microsoft Office up to Word 2016 file inclusion

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.
CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
4.0$0-$5k0.00

Summaryinfo

A vulnerability was found in Microsoft Office 365 Apps/2019/LTSC 2021/LTSC 2024/Word 2016. It has been declared as problematic. Affected is an unknown function. Executing a manipulation can lead to file inclusion. This vulnerability appears as CVE-2026-40421. The attack may be performed from remote. There is no available exploit. Applying a patch is advised to resolve this issue.

Detailsinfo

A vulnerability has been found in Microsoft Office 365 Apps/2019/LTSC 2021/LTSC 2024/Word 2016 and classified as problematic. This vulnerability affects some unknown processing. The manipulation with an unknown input leads to a file inclusion vulnerability. The CWE definition for the vulnerability is CWE-73. The product allows user input to control or influence paths or file names that are used in filesystem operations. As an impact it is known to affect confidentiality. CVE summarizes:

Files or directories accessible to external parties in Microsoft Office Word allows an unauthorized attacker to disclose information locally.

The weakness was presented 05/12/2026 as confirmed security update guide (Website). The advisory is shared for download at msrc.microsoft.com. This vulnerability was named CVE-2026-40421. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Successful exploitation requires user interaction by the victim. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 06/04/2026).

The vulnerability scanner Nessus provides a plugin with the ID 314343 (Security Updates for Microsoft Word Products (May 2026)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 28.1 eliminates this vulnerability. Applying a patch is able to eliminate this problem. The best possible mitigation is suggested to be patching the affected component. A possible mitigation has been published immediately after the disclosure of the vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (314343). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.3
VulDB Meta Temp Score: 4.0

VulDB Base Score: 4.3
VulDB Temp Score: 3.8
VulDB Vector: 🔒
VulDB Reliability: 🔍

Vendor Base Score (Microsoft): 4.3
Vendor Vector (Microsoft): 🔒

CNA Base Score: 4.3
CNA Vector (Microsoft): 🔒

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: File inclusion
CWE: CWE-73
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Unproven

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-DayUnlockUnlockUnlockUnlock
TodayUnlockUnlockUnlockUnlock

Nessus ID: 314343
Nessus Name: Security Updates for Microsoft Word Products (May 2026)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Patch
Status: 🔍

Reaction Time: 🔒
0-Day Time: 🔒
Exposure Time: 🔒

Upgrade: Office 28.1

Timelineinfo

05/12/2026 VulDB entry created
05/12/2026 +0 days Advisory disclosed
05/12/2026 +0 days Countermeasure disclosed
06/04/2026 +23 days VulDB entry last update

Sourcesinfo

Vendor: microsoft.com

Advisory: msrc.microsoft.com
Status: Confirmed

CVE: CVE-2026-40421 (🔒)
GCVE (CVE): GCVE-0-2026-40421
GCVE (VulDB): GCVE-100-363208

Entryinfo

Created: 05/12/2026 19:52
Updated: 06/04/2026 19:50
Changes: 05/12/2026 19:52 (38), 05/12/2026 19:55 (32), 05/13/2026 17:08 (2), 05/19/2026 05:08 (11), 06/04/2026 19:50 (1)
Complete: 🔍
Cache ID: 216::103

VulDB is the best source for vulnerability data and more expert information about this specific topic.

Discussion

No comments yet. Languages: en.

Please log in to comment.

◂ PreviousOverviewNext ▸

Want to know what is going to be exploited?

We predict KEV entries!