CVE-2026-77491

Local information disclosure via out-of-bounds GDI read

Published Sep 8, 2026 · Updated Sep 9, 2026

Out-of-bounds read in Microsoft Windows GDI allows local users to disclose information through an unspecified local interaction. Microsoft identifies the fault as an out-of-bounds read in GDI but has not published the affected function, object type, or malformed input that triggers the read. Exploitation requires no prior privileges but does require user interaction, and the bounded impact is unauthorized disclosure without integrity or availability loss.

CVSS severity5.5
Medium
EPSS probability0.37%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in Microsoft Windows GDI allows local users to disclose information through an unspecified local interaction. Microsoft identifies the fault as an out-of-bounds read in GDI but has not published the affected function, object type, or malformed input that triggers the read. Exploitation requires no prior privileges but does require user interaction, and the bounded impact is unauthorized disclosure without integrity or availability loss.

The record

CVE
CVE-2026-77491
Published
Sep 8, 2026
Updated
Sep 9, 2026
Vendor
Microsoft
Product
Windows Server 2019
Classifications
CWE-125
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=10.0.17763.0 <10.0.17763.9245

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Microsoft · Windows Server 2019version=10.0.17763.0 <10.0.17763.9245
Microsoft · Windows Server 2025 (Server Core installation)version=10.0.26100.0 <10.0.26100.33438
Microsoft · Windows 11, version 25H2version=10.0.26200.0 <10.0.26200.9445
Microsoft · Windows Server 2016 (Server Core installation)version=10.0.14393.0 <10.0.14393.9512
Microsoft · Windows 11, version 24H2version=10.0.26100.0 <10.0.26100.9445
Microsoft · Windows Server 2012 (Server Core installation)version=6.2.9200.0 <6.2.9200.26349
Microsoft · Windows Server 2012version=6.2.9200.0 <6.2.9200.26349
Microsoft · Windows 10 Version 21H2version=10.0.19044.0 <10.0.19044.7725
Microsoft · Windows Server 2016version=10.0.14393.0 <10.0.14393.9512
Microsoft · Windows 10 Version 22H2version=10.0.19045.0 <10.0.19045.7725
Microsoft · Windows Server 2012 R2 (Server Core installation)version=6.3.9600.0 <6.3.9600.23397
Microsoft · Windows Server 2019 (Server Core installation)version=10.0.17763.0 <10.0.17763.9245
Microsoft · Windows 11, version 26H1version=10.0.28000.0 <10.0.28000.2954
Microsoft · Windows 11 Version 23H2version=10.0.22631.0 <10.0.22631.7582
Microsoft · Windows 10 Version 1607version=10.0.14393.0 <10.0.14393.9512
Microsoft · Windows Server 2022version=10.0.20348.0 <10.0.20348.5622
Microsoft · Windows Server 2025version=10.0.26100.0 <10.0.26100.33438
Microsoft · Windows 10 Version 1809version=10.0.17763.0 <10.0.17763.9245
Microsoft · Windows Server 2012 R2version=6.3.9600.0 <6.3.9600.23397

Published CVSS scores

5.5MicrosoftCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
4.8MicrosoftCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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