VDB-345282 · CVE-2026-21258 · Nessus 298976

Microsoft Excel out-of-bounds

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.
4.7	$0-$5k	0.00

Summaryinfo

A vulnerability classified as problematic was found in Microsoft Excel. This vulnerability affects unknown code. The manipulation results in out-of-bounds. This vulnerability is reported as CVE-2026-21258. The attack can be launched remotely. No exploit exists. A patch should be applied to remediate this issue.

Detailsinfo

A vulnerability was found in Microsoft Excel (version unknown). It has been classified as problematic. Affected is an unknown function. The manipulation with an unknown input leads to a out-of-bounds vulnerability. CWE is classifying the issue as CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. This is going to have an impact on confidentiality. CVE summarizes:

Improper input validation in Microsoft Office Excel allows an unauthorized attacker to disclose information locally.

The weakness was disclosed 02/10/2026 as confirmed security update guide (Website). The advisory is available at msrc.microsoft.com. This vulnerability is traded as CVE-2026-21258. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. Successful exploitation requires user interaction by the victim. The technical details are unknown and an exploit is not available. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 02/14/2026).

The vulnerability scanner Nessus provides a plugin with the ID 298976 (Security Updates for Microsoft Excel Products C2R (February 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 (298976). If you want to get best quality of vulnerability data, you may have to visit VulDB.

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: 5.1
VulDB Meta Temp Score: 4.7

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

Vendor Base Score (Microsoft): 5.5
Vendor Vector (Microsoft): 🔒

CNA Base Score: 5.5
CNA Vector (Microsoft): 🔒

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: Out-of-bounds
CWE: CWE-125 / 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: 298976
Nessus Name: Security Updates for Microsoft Excel Products C2R (February 2026)

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Patch
Status: 🔍

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

Timelineinfo

02/10/2026 VulDB entry created
02/10/2026 +0 days Advisory disclosed
02/10/2026 +0 days Countermeasure disclosed
02/14/2026 +3 days VulDB entry last update

Sourcesinfo

Vendor: microsoft.com

Advisory: msrc.microsoft.com
Status: Confirmed

CVE: CVE-2026-21258 (🔒)
GCVE (CVE): GCVE-0-2026-21258
GCVE (VulDB): GCVE-100-345282

Entryinfo

Created: 02/10/2026 19:27
Updated: 02/14/2026 05:13
Changes: 02/10/2026 19:27 (32), 02/10/2026 19:30 (36), 02/11/2026 16:35 (12), 02/14/2026 05:13 (2)
Complete: 🔍
Cache ID: 216::103

If you want to get best quality of vulnerability data, you may have to visit VulDB.