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NVD / CVE Program· CNA microsoft

CVE-2026-81963: Windows Update Stack Elevation of Privilege Vulnerability

Noroxi assessment

Priority: This week (action score 61/100)

  • CISA has confirmed exploitation in the wild (Sep 8, 2026). Remediation deadline for US federal agencies: Sep 22, 2026.
  • Probability of exploitation in the next 30 days: 0.39% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Windows 11 Version 23H2 for ARM64-based Systems 10.0.22631.7582; Windows 11 Version 23H2 for x64-based Systems 10.0.22631.7582; Windows 11 Version 24H2 for ARM64-based Systems 10.0.26100.9445.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Don’t wait for the next maintenance window. Upgrade to Windows 11 Version 23H2 for ARM64-based Systems 10.0.22631.7582; Windows 11 Version 23H2 for x64-based Systems 10.0.22631.7582; Windows 11 Version 24H2 for ARM64-based Systems 10.0.26100.9445 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · CISA KEV · FIRST EPSS

Improper link resolution before file access ('link following') in Windows Update Stack allows an authorized attacker to elevate privileges locally.

HighCVSS 7.8 · v3.1KEVWeaponized Fix available
Published
Sep 8, 2026
Updated
Oct 8, 2026
EPSS
0.3% · 33th percentile

Report tools

JSON

Action score

61

This week

Don’t wait for the next maintenance window.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
30 / 30 · Listed
EPSS
0 / 30 · 0.3%

CISA SSVC decision

Exploitation
active
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · microsoft
7.8
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Actively exploited in the wild

CISA added this to its Known Exploited Vulnerabilities catalog on Sep 8, 2026. That signals real attacks, not theory.

Remediation deadline for US federal agencies: Sep 22, 2026.

Get told when this record changes

  • In CISA KEV: exploitation in the wild confirmed
  • Weaponized exploit exists
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-81963

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
microsoftwindows 11 23h2
microsoftwindows 11 24h2
microsoftwindows 11 25h2
microsoftwindows 11 26h1
microsoftwindows server 2025

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • microsoft windows server 2025before 10.0.26100.33438

Versions reported by the vendor

Affected version ranges reported by the assigning authority (microsoft). Independent of NVD's CPE analysis and usually ahead of it.

  • Microsoft Windows 11 version 23H2

    • 10.0.22631.0 and later · before 10.0.22631.7582affected

  • Microsoft Windows 11 Version 23H2

    • 10.0.22631.0 and later · before 10.0.22631.7582affected

  • Microsoft Windows 11 Version 24H2

    • 10.0.26100.0 and later · before 10.0.26100.9445affected

  • Microsoft Windows 11 Version 25H2

    • 10.0.26200.0 and later · before 10.0.26200.9445affected

  • Microsoft Windows 11 version 26H1

    • 10.0.28000.0 and later · before 10.0.28000.2954affected

  • Microsoft Windows Server 2025

    • 10.0.26100.0 and later · before 10.0.26100.33438affected

  • Microsoft Windows Server 2025 (Server Core installation)

    • 10.0.26100.0 and later · before 10.0.26100.33438affected

Same product

microsoft: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-45657Windows Kernel Remote Code Execution Vulnerability
    44Plan
  • CVE-2026-41096Windows DNS Client Remote Code Execution Vulnerability
    40Plan
  • CVE-2025-9491Microsoft Windows LNK File UI Misrepresentation Remote Code Execution Vulnerability
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-72949Sep 8, 2026 · Windows SMB Server Network Transport Driver (srvnet.sys) Denial of Service Vulnerability
    30Monitor
  • ← EarlierCVE-2026-80083Sep 8, 2026 · Windows Hyper-V Remote Code Execution Vulnerability
    35Monitor
  • Later →CVE-2026-83498Sep 8, 2026 · Windows Virtualization-Based Security (VBS) Enclave Elevation of Privilege Vulnerability
    31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Windows 11 Version 23H2 for ARM64-based Systems10.0.22631.7582 · KB5122880Microsoft (MSRC)
Windows 11 Version 23H2 for x64-based Systems10.0.22631.7582 · KB5122880Microsoft (MSRC)
Windows 11 Version 24H2 for ARM64-based Systems10.0.26100.9445 · KB5124008Microsoft (MSRC)
Windows 11 Version 24H2 for x64-based Systems10.0.26100.9445 · KB5124008Microsoft (MSRC)
Windows 11 Version 25H2 for ARM64-based Systems10.0.26200.9445 · KB5124008Microsoft (MSRC)
Windows 11 Version 25H2 for x64-based Systems10.0.26200.9445 · KB5124008Microsoft (MSRC)
Windows 11 Version 26H1 for ARM64-based Systems10.0.28000.2954 · KB5124012Microsoft (MSRC)
Windows 11 version 26H1 for x64-based Systems10.0.28000.2954 · KB5124012Microsoft (MSRC)
Windows Server 202510.0.26100.33438 · KB5122871Microsoft (MSRC)
Windows Server 2025 (Server Core installation)10.0.26100.33438 · KB5122871Microsoft (MSRC)

Exploit status

Weaponized

A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.

Evidence

  • Proof-of-concept repository on GitHub ×1

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Proof-of-concept repository on GitHubstars:02026-10-19

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. CISA KEV-1 d
  2. Published
  3. First PoC+40 d
  4. TodayOct 26, 2026+48 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-10220235 days apartWindows Container Isolation FS Filter Driver (unionfs.sys) Elevation of Privilege Vulnerability
    31Monitor
  • CVE-2026-6967335 days apartWindows Update Elevation of Privilege Vulnerability
    31Monitor
  • CVE-2026-693790 days apartWindows NTFS Elevation of Privilege Vulnerability
    28Monitor
  • CVE-2026-694250 days apartWindows NTFS Tampering Vulnerability
    18Monitor
  • CVE-2026-697710 days apartWindows Container Manager Service Security Feature Bypass Vulnerability
    18Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-59 · Improper Link Resolution Before File Access ('Link Following')

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (1 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records