VDB-378868 · CVE-2026-55138 · GCVE-0-2026-55138

Microsoft Office Excel null pointer dereference

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.
2.8	$0-$5k	0.00

Summaryinfo

A vulnerability classified as problematic was found in Microsoft Office. The affected element is an unknown function of the component Excel. Executing a manipulation can lead to null pointer dereference. This vulnerability appears as CVE-2026-55138. The attack requires local access. There is no available exploit.

Detailsinfo

A vulnerability has been found in Microsoft Office (version unknown) and classified as problematic. This vulnerability affects an unknown function of the component Excel. The manipulation with an unknown input leads to a null pointer dereference vulnerability. The CWE definition for the vulnerability is CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. As an impact it is known to affect confidentiality. CVE summarizes:

Untrusted pointer dereference in Microsoft Office Excel allows an unauthorized attacker to disclose information locally.

The advisory is shared for download at msrc.microsoft.com. This vulnerability was named CVE-2026-55138 since 06/16/2026. The exploitation appears to be easy. The attack needs to be approached locally. 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 07/15/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

Office Suite Software

Vendor

Microsoft

Name

Office

License

commercial

Website

Vendor: https://www.microsoft.com/

CPE 2.3info

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CPE 2.2info

🔒

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 2.8
VulDB Meta Temp Score: 2.8

VulDB Base Score: 2.8
VulDB Temp Score: 2.8
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

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

Exploitinginfo

Class: Null pointer dereference
CWE: CWE-476 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

06/16/2026 CVE reserved
07/14/2026 +28 days VulDB entry created
07/15/2026 +0 days Advisory disclosed
07/15/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: microsoft.com

Advisory: msrc.microsoft.com
Status: Confirmed

CVE: CVE-2026-55138 (🔒)
GCVE (CVE): GCVE-0-2026-55138
GCVE (VulDB): GCVE-100-378868

Entryinfo

Created: 07/15/2026 00:19
Changes: 07/15/2026 00:19 (52)
Complete: 🔍
Cache ID: 216::103