Microsoft Windows up to Server 2025 Win32k buffer 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.
8.8$25k-$100k0.68

Summaryinfo

A vulnerability was found in Microsoft Windows. It has been declared as very critical. This impacts an unknown function of the component Win32k. The manipulation results in buffer overflow. This vulnerability is reported as CVE-2026-54986. The attack requires a local approach. No exploit exists.

Detailsinfo

A vulnerability, which was classified as very critical, was found in Microsoft Windows. Affected is some unknown processing of the component Win32k. The manipulation with an unknown input leads to a buffer overflow vulnerability. CWE is classifying the issue as CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

Heap-based buffer overflow in Windows Win32K allows an authorized attacker to elevate privileges locally.

The advisory is shared for download at msrc.microsoft.com. This vulnerability is traded as CVE-2026-54986 since 06/16/2026. The exploitability is told 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 $25k-$100k (estimation calculated on 07/14/2026).

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

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

Productinfo

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Version

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.8
VulDB Meta Temp Score: 8.8

VulDB Base Score: 8.8
VulDB Temp Score: 8.8
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: Buffer overflow
CWE: CWE-120 / 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: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

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

Sourcesinfo

Vendor: microsoft.com
Product: microsoft.com

Advisory: msrc.microsoft.com
Status: Confirmed

CVE: CVE-2026-54986 (🔒)
GCVE (CVE): GCVE-0-2026-54986
GCVE (VulDB): GCVE-100-378552
scip Labs: https://www.scip.ch/en/?labs.20161215

Entryinfo

Created: 07/14/2026 21:52
Changes: 07/14/2026 21:52 (53)
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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