VDB-350033 · CVE-2026-26108 · Nessus 301778

Microsoft Excel heap-based overflow

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.
6.7	$0-$5k	0.00

Summaryinfo

A vulnerability was found in Microsoft Excel. It has been classified as critical. This affects an unknown part. The manipulation leads to heap-based overflow. This vulnerability is listed as CVE-2026-26108. The attack may be initiated remotely. There is no available exploit. It is suggested to install a patch to address this issue.

Detailsinfo

A vulnerability was found in Microsoft Excel (unknown version) and classified as critical. This issue affects an unknown code block. The manipulation with an unknown input leads to a heap-based overflow vulnerability. Using CWE to declare the problem leads to CWE-122. A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc(). Impacted is confidentiality, integrity, and availability. The summary by CVE is:

Heap-based buffer overflow in Microsoft Office Excel allows an unauthorized attacker to execute code locally.

The weakness was presented 03/10/2026 as confirmed security update guide (Website). The advisory is shared at msrc.microsoft.com. The identification of this vulnerability is CVE-2026-26108. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. It demands that the victim is doing some kind of user interaction. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 03/13/2026).

The vulnerability scanner Nessus provides a plugin with the ID 301778 (Security Updates for Microsoft Excel Products C2R (March 2026)), which helps to determine the existence of the flaw in a target environment.

Applying a patch is able to eliminate this problem. A possible mitigation has been published immediately after the disclosure of the vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (301778). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

Spreadsheet Software

Vendor

Microsoft

Name

Excel

License

commercial

Website

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

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.3
VulDB Meta Temp Score: 6.7

VulDB Base Score: 6.3
VulDB Temp Score: 5.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

Vendor Base Score (Microsoft): 7.8
Vendor Vector (Microsoft): 🔒

CNA Base Score: 7.8
CNA Vector (Microsoft): 🔒

CVSSv2info

AV	AC	Au	C	I	A
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💳	💳	💳	💳	💳	💳
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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Heap-based overflow
CWE: CWE-122 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Yes

Availability: 🔒
Status: Unproven

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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

Nessus ID: 301778
Nessus Name: Security Updates for Microsoft Excel Products C2R (March 2026)

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Patch
Status: 🔍

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

Timelineinfo

03/10/2026 VulDB entry created
03/10/2026 +0 days Advisory disclosed
03/10/2026 +0 days Countermeasure disclosed
03/13/2026 +2 days VulDB entry last update