CVE-2026-83798

Local spoofing via improper signature verification

Published Oct 13, 2026 · Updated Oct 13, 2026

Signature verification failure in Microsoft Windows Update Stack allows local users to perform spoofing via unspecified vectors. The supplied source identifies improper cryptographic-signature verification, but the affected function, signed object, and incorrect validation step could not be verified from public records. Authorized local access is required; the spoofed identity or content and any further consequences remain unspecified.

CVSS severityUnavailable
Unscored
EPSS probability0.21%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Signature verification failure in Microsoft Windows Update Stack allows local users to perform spoofing via unspecified vectors. The supplied source identifies improper cryptographic-signature verification, but the affected function, signed object, and incorrect validation step could not be verified from public records. Authorized local access is required; the spoofed identity or content and any further consequences remain unspecified.

The record

CVE
CVE-2026-83798
Published
Oct 13, 2026
Updated
Oct 13, 2026
Vendor
Microsoft Corporation
Product
Windows Server 2019
Classifications
Unavailable
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Oct 13, 2026CVE publishedPublication date reported by the CVE source.
  2. Oct 13, 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 <10.0.17763.9376

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

Microsoft Corporation · Windows Server 2019version=10.0.17763.0 <10.0.17763.9376
Microsoft Corporation · Windows Server 2025 (Server Core installation)version=10.0.26100.0 <10.0.26100.33650
Microsoft Corporation · Windows 11, version 25H2version=10.0.26200.0 <10.0.26200.9711
Microsoft Corporation · Windows Server 2016 (Server Core installation)version=10.0.14393.0 <10.0.14393.9612
Microsoft Corporation · Windows 11, version 24H2version=10.0.26100.0 <10.0.26100.9711
Microsoft Corporation · Windows Server 2012 (Server Core installation)version=6.2.9200.0 <6.2.9200.26434
Microsoft Corporation · Windows Server 2012version=6.2.9200.0 <6.2.9200.26434
Microsoft Corporation · Windows 10 Version 21H2version=10.0.19044.0 <10.0.19044.7807
Microsoft Corporation · Windows Server 2016version=10.0.14393.0 <10.0.14393.9612
Microsoft Corporation · Windows 11, version 26H2version=10.0.26300.0 <10.0.26300.9711
Microsoft Corporation · Windows 10 Version 22H2version=10.0.19045.0 <10.0.19044.7807
Microsoft Corporation · Windows Server 2012 R2 (Server Core installation)version=6.3.9600.0 <6.3.9600.23470
Microsoft Corporation · Windows Server 2019 (Server Core installation)version=10.0.17763.0 <10.0.17763.9376
Microsoft Corporation · Windows 11, version 26H1version=10.0.28000.0 <10.0.28000.3231
Microsoft Corporation · Windows 11 Version 23H2version=10.0.22631.0 <10.0.22631.7652
Microsoft Corporation · Windows 10 Version 1607version=10.0.14393.0 <10.0.14393.9612
Microsoft Corporation · Windows Server 2022version=10.0.20348.0 <10.0.20348.5761
Microsoft Corporation · Windows Server 2025version=10.0.26100.0 <10.0.26100.33650
Microsoft Corporation · Windows 10 Version 1809version=10.0.17763.0 <10.0.17763.9376
Microsoft Corporation · Windows Server 2012 R2version=6.3.9600.0 <6.3.9600.23470

Published CVSS scores

No CVSS assessment is available in this record.

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.

Activity data is delayed. The latest report is Sep 28, 2026.

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

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

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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