Microsoft Windows up to Server 2025 GDI 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.
4.1$0-$5k0.00+

Summaryinfo

A vulnerability identified as problematic has been detected in Microsoft Windows. Affected by this issue is some unknown functionality of the component GDI. The manipulation leads to out-of-bounds. This vulnerability is traded as CVE-2026-77491. An attack has to be approached locally. There is no exploit available. It is recommended to apply a patch to fix this issue.

Detailsinfo

A vulnerability was found in Microsoft Windows. It has been rated as problematic. This issue affects some unknown functionality of the component GDI. 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 Windows GDI 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-2026-77491 since 08/20/2026. The exploitation is known to be easy. Attacking locally is a requirement. It demands that the victim is doing some kind of user interaction. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 09/09/2026).

Applying a patch is able to eliminate this problem.

Be aware that VulDB is the high quality source 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: 4.1
VulDB Meta Temp Score: 4.1

VulDB Base Score: 2.8
VulDB Temp Score: 2.7
VulDB Vector: 🔒
VulDB Reliability: 🔍

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

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: Partially

Availability: 🔒
Status: Not defined
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

08/20/2026 CVE reserved
09/09/2026 +20 days Advisory disclosed
09/09/2026 +0 days VulDB entry created
09/09/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: microsoft.com
Product: microsoft.com

Advisory: msrc.microsoft.com
Status: Confirmed

CVE: CVE-2026-77491 (🔒)
GCVE (CVE): GCVE-0-2026-77491
GCVE (VulDB): GCVE-100-401039
scip Labs: https://www.scip.ch/en/?labs.20161215

Entryinfo

Created: 09/09/2026 02:48
Changes: 09/09/2026 02:48 (63)
Complete: 🔍
Cache ID: 216::103

Be aware that VulDB is the high quality source for vulnerability data.

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