CVE-2026-42989
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedImproper link resolution before file access ('link following') in Winlogon allows an authorized attacker to elevate privileges locally.
In the news
Third-party coverage- Microsoft June 2026 Patch Tuesday fixes 6 zero-days, 200 flaws
- Microsoft CVE Summary - Bleeping Computer
Surfaced from public web coverage — external links open in a new tab.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceThis is a link following (symlink attack) vulnerability in Winlogon, a core Windows authentication component. The vulnerability allows a local attacker to manipulate file access through improper validation of symbolic links, potentially enabling privilege escalation from a standard user account to higher system privileges.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 10.0.14393.9234< 10.0.17763.8880< 10.0.19044.7417< 10.0.19045.7417< 10.0.22631.7219< 10.0.26100.8655< 10.0.26200.8655< 10.0.28000.2269CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Check Windows version against affected rangesRun 'winver' or 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' to obtain the Windows build number. Compare against: Windows 10 1607 < 14393.9234, 1809 < 17763.8880, 21h2 < 19044.7417, 22h2 < 19045.7417; Windows 11 23h2 < 22631.7219, 24h2 < 26100.8655, 25h2 < 26200.8655, 26h1 < 28000.2269Affected if Your installed build number is lower than the corresponding threshold for your Windows version and build
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Verify Winlogon service is runningOpen Services.msc and locate 'Windows Logon Application (Winlogon)' or run 'Get-Service Winlogon' in PowerShellAffected if Winlogon service is present and running (this is the default state; the vulnerability applies to any running Winlogon instance on an unpatched version)
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Inspect Winlogon-accessed directories for symbolic links and junction pointsUse 'Get-Item -Path C:\Windows\System32\winlogon.exe | Format-List *' to verify the executable integrity. Then run 'Get-ChildItem -Path C:\Users -Recurse -ErrorAction SilentlyContinue | Where-Object {$_.LinkType -eq "SymbolicLink" -or $_.LinkType -eq "Junction"}' to enumerate any symbolic links or junction points in user profile directories that Winlogon may access during logonAffected if Unexpected symbolic links or junction points exist in directories that Winlogon accesses (such as user profile folders, %TEMP%, or system32 paths)
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Check for suspicious files in Winlogon-accessed pathsReview the contents of C:\Windows\Temp, %TEMP%, and user profile AppData\Local\Temp directories for newly created or recently modified executable files, DLLs, or configuration files that may have been placed via link manipulation. Use 'Get-ChildItem -Path C:\Windows\Temp -Recurse -File | Where-Object {$_.LastWriteTime -gt (Get-Date).AddDays(-7)}' to find recently created filesAffected if Unexpected executable files, DLLs, or scripts appear in these locations with creation dates after the vulnerability disclosure or after a potential attack period
You are affected if your Windows build version falls below the thresholds listed and suspicious symbolic links or unexpected files exist in Winlogon-accessed directories.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped10.0.14393.923410.0.17763.888010.0.19044.7417
Apply the vendor security update for Windows that addresses this vulnerability in Winlogon. Until patched, monitor for unauthorized modifications to file system locations that Winlogon accesses, and restrict file system access for standard users.
Upgrade to Windows 10 build 10.0.14393.9234 or higher (1607), 10.0.17763.8880 or higher (1809), 10.0.19044.7417 or higher (21h2), 10.0.19045.7417 or higher (22h2); or Windows 11 build 10.0.22631.7219 or higher (23h2), 10.0.26100.8655 or higher (24h2), 10.0.26200.8655 or higher (25h2), 10.0.28000.226
- 1. Identify the current Windows version and build number by running 'winver' or 'systeminfo' in Command Prompt
- 2. Determine which Windows 10 or 11 version/edition is installed (e.g., 1607, 1809, 21h2, 22h2, 23h2, 24h2, 25h2, or 26h1)
- 3. Apply the appropriate Windows Update for the installed version that includes the security fix for CVE-2026-42989
- 4. Alternatively, download and install the latest cumulative update (LCU) for the specific Windows version from Microsoft Update Catalog
- 5. Restart the system after applying the update
- 6. Verify the fix by checking the installed build number matches or exceeds the fixed version for your Windows release
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation6.0 h
- Implementation12.0 h
- Testing10.0 h
- Review / QA6.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-42989 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-42989 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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