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CVE-2026-81963

Exploitation: active CVSS 7.8 HIGH

CVSS base score: 7.8 (High) vendor CNA · v3.1

Score assigned by the vendor's own CVE Numbering Authority (CNA); CISA's Vulnrichment program adds a score only when the CNA omits one.

Microsoft Windows Link Following Vulnerability

Vendor: Microsoft   Product: Windows

Description

Microsoft Windows Update Stack contains a link following vulnerability that allows a local attacker to escalate privileges locally up to SYSTEM.

Lifecycle Timeline

Each milestone comes from a different source, so gaps between them are gaps in what those sources publish, not evidence that nothing happened. EPSS history for this CVE holds 14 points from 2026-09-09, tracked daily from 2026-09-09; earlier points are weekly, which dates a spike to within a week. Peak probability 0.6% on 2026-09-09.

Published Applicability

CVE List v5 (CNA container) 14 affected · 0 fixed · 0 not affected

Check whether a specific version is affected →

What each source publishes about which product versions carry this vulnerability, kept as written rather than merged. Absence here means no source has published applicability data, not that nothing is affected.

Research & News Coverage

DateSourceArticle
2026-09-14 Check Point Research 14th September – Threat Intelligence Report
2026-09-08 SANS Internet Storm Center September 2026 Microsoft Patch Tuesday, (Tue, Sep 8th)

Articles from monitored vendor research blogs and security news feeds that specifically mention this CVE. Coverage begins when feed monitoring started; earlier articles are not indexed.

Detection & Exploitation

Scan
none published
Exploit / Pen Test
none published
Network IDS/IPS
none published
Host / SIEM
none published

Blind spot. No public detection — verify by version/patch. Nothing in the monitored scanner, IDS, SIEM or offensive-tool collections references this CVE, so exposure has to be established from asset inventory and patch level rather than from a signature.

Coverage across public collections only: Nuclei and OpenVAS NVT (scan); Snort and Suricata ET Open (network); Sigma and YARA (host/SIEM); Metasploit, Exploit-DB and public GitHub repositories (exploit). Absence here means nothing public was found, not that detection is impossible.
GitHub PoC repositories are collected automatically by PoC-in-GitHub (CC0) and are not vetted: some are fakes and some are malware. Treat them as evidence that code was published, not as code to run.
OpenVAS coverage derives from the Greenbone Community Feed, made available under the Open Database License (ODbL) v1.0; its individual Vulnerability Tests are licensed GNU GPL v2.

Microsoft Assessment

published by the affected vendor via MSRC

Windows Update Stack Elevation of Privilege Vulnerability

Exploitation Detected
Yes
No
Important
Elevation of Privilege
Windows Update Stack
2026-09-08
CWE-59: Improper Link Resolution Before File Access ('Link Following'), CWE-284: Improper Access Control

The vendor's own judgement about their own code, shown alongside CISA's rather than merged into it. The exploitability index is a forward-looking prediction, distinct from a CVSS severity or CISA's SSVC decision, and vendors often report observed exploitation before a CVE reaches the KEV catalog. Vendor advisory →

CISA Assessment (Vulnrichment / SSVC)

active
no
total
—
7.8 HIGH
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
CWE-59 — Improper Link Resolution Before File Access ('Link Following')
2026-09-08

KEV Catalog Status

2026-09-08
2026-09-22
Unknown

Listed By

SourceDateRecord
CISA KEV 2026-09-08 source record →
CISA Vulnrichment 2026-09-08 source record →

Referenced in Advisories

DateAdvisoryIssuer
2026-09-09 Microsoft Releases September 2026 Security Updates JPCERT/CC
2026-09-08 CISA Adds Four Known Exploited Vulnerabilities to Catalog CISA

Weaponization Timeline — Offensive & Testing Tools

No exploit-tool sightings recorded for this CVE.

Evidence tiers are explained on the About page — a merged Metasploit module is far stronger evidence than a distro package mention.

External References