Microsoft Office/Word up to Mac out-of-bounds

CVSS Meta Temp Score
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CTI Interest Score
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3.2$0-$5k0.00

Summaryinfo

A vulnerability was found in Microsoft Office and Word up to Mac. It has been classified as problematic. This affects an unknown function. The manipulation leads to out-of-bounds. This vulnerability is referenced as CVE-2026-66809. The attack can only be performed from a local environment. No exploit is available. To fix this issue, it is recommended to deploy a patch.

Detailsinfo

A vulnerability was found in Microsoft Office and Word up to Mac and classified as problematic. This issue affects an unknown code block. The manipulation with an unknown input leads to a out-of-bounds vulnerability. Using CWE to declare the problem leads to CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. Impacted is confidentiality. The summary by CVE is:

Out-of-bounds read in Microsoft Office allows an unauthorized attacker to disclose information locally.

It is possible to read the advisory at msrc.microsoft.com. The identification of this vulnerability is CVE-2026-66809 since 07/27/2026. The exploitation is known to be easy. Attacking locally is a requirement. The technical details are unknown and an exploit is not publicly available.

Applying a patch is able to eliminate this problem.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-56752). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 3.3
VulDB Meta Temp Score: 3.2

VulDB Base Score: 3.3
VulDB Temp Score: 3.2
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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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: No

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Patch
Status: 🔍

0-Day Time: 🔒

Timelineinfo

07/27/2026 CVE reserved
08/11/2026 +15 days Advisory disclosed
08/11/2026 +0 days VulDB entry created
08/17/2026 +6 days VulDB entry last update

Sourcesinfo

Vendor: microsoft.com

Advisory: msrc.microsoft.com
Status: Confirmed

CVE: CVE-2026-66809 (🔒)
GCVE (CVE): GCVE-0-2026-66809
GCVE (VulDB): GCVE-100-388715
EUVD: 🔒

Entryinfo

Created: 08/11/2026 23:42
Updated: 08/17/2026 02:00
Changes: 08/11/2026 23:42 (53), 08/17/2026 02:00 (1)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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