Microsoft Windows 11 26H1 double free

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 (≈)
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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.
8.0$5k-$25k2.68-

Summaryinfo

A vulnerability was found in Microsoft Windows 11 26H1. It has been declared as very critical. The affected element is an unknown function. Such manipulation leads to double free. This vulnerability is referenced as CVE-2026-85921. The attack can only be performed from a local environment. No exploit is available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in Microsoft Windows 11 26H1. It has been rated as very critical. Affected by this issue is some unknown processing. The manipulation with an unknown input leads to a double free vulnerability. Using CWE to declare the problem leads to CWE-415. The product calls free() twice on the same memory address, potentially leading to modification of unexpected memory locations. Impacted is confidentiality, integrity, and availability. CVE summarizes:

Double free in Windows Secure Kernel Mode allows an authorized attacker to elevate privileges locally.

The advisory is shared for download at msrc.microsoft.com. This vulnerability is handled as CVE-2026-85921 since 09/04/2026. The exploitation is known to be easy. The attack needs to be approached locally. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 09/14/2026).

Upgrading to version 10.0.28000.2956 eliminates this vulnerability.

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: 8.2
VulDB Meta Temp Score: 8.0

VulDB Base Score: 8.2
VulDB Temp Score: 7.8
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 8.2
CNA Vector (microsoft): 🔒

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Double free
CWE: CWE-415 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

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

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Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Windows 10.0.28000.2956

Timelineinfo

09/04/2026 CVE reserved
09/14/2026 +10 days Advisory disclosed
09/14/2026 +0 days VulDB entry created
09/14/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: microsoft.com
Product: microsoft.com

Advisory: msrc.microsoft.com
Status: Confirmed

CVE: CVE-2026-85921 (🔒)
GCVE (CVE): GCVE-0-2026-85921
GCVE (VulDB): GCVE-100-403640

Entryinfo

Created: 09/14/2026 19:50
Changes: 09/14/2026 19:50 (63)
Complete: 🔍
Cache ID: 216::103

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

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