ExploitedIn CISA KEVFix available

CVE-2026-81963

Q: Is CVE-2026-81963 actively exploited?

Yes. CVE-2026-81963 is on the CISA Known Exploited Vulnerabilities (KEV) catalog, meaning it has been confirmed as actively exploited in the wild. CISA requires federal agencies to patch by 2026-09-22.

Q: What is the CVSS score for CVE-2026-81963?

CVE-2026-81963 has a CVSS v3 base score of 7.8 (HIGH severity), with vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

Exploitation confirmed. First attested on 2026-09-08 by CISA-ADP, CISA KEV, GCVE · previdian.

Published2026-09-08
Fixed in10.0.22631.7582
WeaknessCWE-284 · CWE-59

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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

Timeline

dates in UTC

2026-09-08Added to the CISA KEV catalogCISA KEV
2026-09-08Listed as exploited by GCVEGCVE
2026-09-08Exploitation first reportedCISA KEV
2026-09-0818:21CVE publishedNVD
2026-09-0818:44SSVC exploitation set to activeCISA-ADP

Observed activity

isMalicious corpus · updated 2026-10-24 21:37 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-81963?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-81963?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Microsoft windows 11 23h2

Branch	Affected	Fixed in	Source
10.0	< 10.0.22631.7582	10.0.22631.7582	NVD

Microsoft windows 11 24h2

Branch	Affected	Fixed in	Source
10.0	< 10.0.26100.9445	10.0.26100.9445	NVD

Microsoft windows 11 25h2

Branch	Affected	Fixed in	Source
10.0	< 10.0.26200.9445	10.0.26200.9445	NVD

2 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Update Microsoft windows 11 23h2 to 10.0.22631.7582
CISA’s required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.due 2026-09-22

Advisories and patches

msrc.microsoft.comPatch · Vendor Advisory

Detection

read 2026-10-23 19:25 UTC

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: 1 repository, unverifiedrsah35404-star/stunning-octo-doodle

CISA Known Exploited Vulnerability

Date Added: 2026-09-08
Patch Due Date: 2026-09-22
Ransomware Use: Unknown
Required Action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

Sources

NVDCVE recordread 2026-10-23
CISA KEVKEV entry2026-09-08
GCVEexploitation2026-09-08
CISA-ADPSSVC decisionactive2026-09-08
OpenCVESSVC decisionactive—
CNACVSS 3.17.8read 2026-10-23
CNAweakness (CWE)CWE-284, CWE-59read 2026-10-23
FIRST EPSSEPSS score0.4 %2026-10-24
PoC-in-GitHubproof of concept1read 2026-10-23

Technical details

CVSS v3 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Published: 2026-09-08
Last Modified: 2026-09-09
NVD status: Analyzed

Frequently asked questions

What is CVE-2026-81963?

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

Is CVE-2026-81963 actively exploited?

Yes. CVE-2026-81963 is on the CISA Known Exploited Vulnerabilities (KEV) catalog, meaning it has been confirmed as actively exploited in the wild. CISA requires federal agencies to patch by 2026-09-22.

What is the CVSS score for CVE-2026-81963?

CVE-2026-81963 has a CVSS v3 base score of 7.8 (HIGH severity), with vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

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