dbcve.org
Windows 10 1607Operating system · Microsoft

CVE-2026-35421

HIGH · 7.8 CVSS v3.1 Published 2026-05-12
Fix available
A fix is available. Upgrade to 10.0.14393.9140 / 10.0.17763.8755 or later.
See remediation →
81/100
Remediation priority · High
No privileges

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 · unedited
Heap-based buffer overflow in Windows GDI allows an unauthorized attacker to execute code locally.

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 confidence

Heap-based buffer overflow vulnerability in Windows Graphics Device Interface (GDI) allows a local attacker to execute arbitrary code via specially crafted graphic operations that overflow heap memory allocations.

MitigationApply Microsoft security updates for Windows GDI when available. Prioritize patching systems with direct user access and workstations running untrusted graphical content.

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
Windows 10 1607Operating system
Affected:< 10.0.14393.9140
Windows 10 1809Operating system
Affected:< 10.0.17763.8755
Windows 10 21h2Operating system
Affected:< 10.0.19044.7291
Windows 10 22h2Operating system
Affected:< 10.0.19045.7291
Windows 11 23h2Operating system
Affected:< 10.0.22631.7079
Windows 11 24h2Operating system
Affected:< 10.0.26100.8390
Windows 11 25h2Operating system
Affected:< 10.0.26200.8390
Windows 11 26h1Operating system
Affected:< 10.0.28000.2113

CVSS 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
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify Windows version and build number
    Run 'winver' from command prompt to see OS version and build, or use 'systeminfo' and look for 'OS Name' and 'OS Version' fields
    Affected if The displayed build number falls below any of these thresholds: Windows 10 1607 < 14393.9140, Windows 10 1809 < 17763.8755, Windows 10 21h2 < 19044.7291, Windows 10 22h2 < 19045.7291, Windows 11 23h2 < 22631.7079, Windows 11 24h2 < 26100.8390, Windows 11 25h2 < 26200.8390, Windows 11 26h1 < 28000.21
  2. Check CurrentVersion registry key
    Open Registry Editor and navigate to HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion, or run 'reg query "HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion" /v CurrentBuild' and /v DisplayVersion
    Affected if The CurrentBuild value is lower than the affected build numbers listed above for your Windows release version
  3. Confirm Windows 10 or 11 edition
    Run 'winver' or check System Properties to verify if the system is Windows 10 or Windows 11, noting the specific release (such as 1809, 21h2, 22h2, 23h2, 24h2, 25h2, or 26h1)
    Affected if The system is any Windows 10 or Windows 11 release listed in the affected versions and the build is below the corresponding threshold for that release

A system is affected if it runs any Windows 10 or Windows 11 version with a build number lower than the threshold specified for that particular release.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 · scoped
Upgrade available Upgrade to 10.0.14393.9140 / 10.0.17763.8755 / 10.0.19044.7291 or later
Fixed in 10.0.14393.914010.0.17763.875510.0.19044.7291
Interim mitigation

Apply Microsoft security updates for Windows GDI when available. Prioritize patching systems with direct user access and workstations running untrusted graphical content.

Recommended fix High confidence

Windows 10 1607: KB5055527 (10.0.14393.9140) | Windows 10 1809: KB5055528 (10.0.17763.8755) | Windows 10 21h2: KB5055518 (10.0.19044.7291) | Windows 10 22h2: KB5055518 (10.0.19045.7291) | Windows 11 23h2: KB5055523 (10.0.22631.7079) | Windows 11 24h2: KB5055519 (10.0.26100.8390) | Windows 11 25h2: K

  1. Open Windows Settings and navigate to Update & Security > Windows Update
  2. Click Check for updates to download and install the latest cumulative update
  3. Alternatively, manually download the appropriate security update from the Microsoft Update Catalog for your Windows version: KB5055527 (Windows 10 1607), KB5055528 (Windows 10 1809), KB5055518 (Windows 10 21h2/22h2), KB5055523 (Windows 11 23h2), KB5055519 (Windows 11 24h2), KB5055520 (Windows 11 25h2), KB5055521 (Windows 11 26h1)
  4. Restart the system after the update is installed
  5. Verify the installed update by checking the Windows Update history to confirm theKB number is listed as successfully installed

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Windows 10 1607 Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA3.0 h
15.0 hours of engineering $2,560
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,096.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2026-35421 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-35421 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data