CVE-2026-55012
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 · uneditedInteger overflow or wraparound in Microsoft Defender allows an unauthorized attacker to execute code locally.
In the news
Third-party coverage- Microsoft July 2026 Patch Tuesday fixes massive 570 flaws, 3 zero-days
- Records Are Made to Be Broken: Patch Tuesday Raises Triage Stakes
- 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 confidenceA local integer overflow or wraparound vulnerability exists in Microsoft Defender antivirus software. The vulnerability allows an unauthorized local attacker to execute arbitrary code by exploiting the integer overflow condition, potentially achieving elevated privileges on the affected system.
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< 1.1.26060.3008CVSS 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 checksWork through these to decide whether this CVE applies to you.
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Confirm Windows Defender is installedOpen PowerShell and run: Get-MpComputerStatus | Select-Object AntivirusEnabled, AntispywareEnabledAffected if If both AntivirusEnabled and AntispywareEnabled return False, Defender is not active and this CVE does not apply. If True, continue to version check.
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Retrieve the Malware Protection Engine versionRun: Get-MpComputerStatus | Select-Object AntivirusSignatureVersion, AntivirusEngineVersionAffected if The AntivirusEngineVersion field shows the engine version. If this value is missing or returns an error, the engine may not be fully initialized.
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Identify the exact engine version numberRun: (Get-MpComputerStatus).EngineVersion or check registry at HKLM\SOFTWARE\Microsoft\Microsoft Antimalware\EngineVersionAffected if Extract the full version number (e.g., 1.1.26060.3008). This is the precise value to compare against the affected range.
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Compare installed version to the affected rangeVerify the engine version number against < 1.1.26060.3008. Any version lower than 1.1.26060.3008 is affected.Affected if If the installed version is less than 1.1.26060.3008 (for example, 1.1.26050.0 or 1.1.24000.1000), the system is vulnerable to this integer overflow.
A system is affected if Windows Defender is enabled and the Malware Protection Engine version is lower than 1.1.26060.3008.
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.
From vendor data1.1.26060.3008
Apply Microsoft security updates for Microsoft Defender when released. Ensure Windows systems have the latest Defender definitions and patches installed. Restrict local administrative privileges where possible to limit attack surface.
- Consultation2.0 h
- Implementation4.0 h
- Testing6.0 h
- Review / QA3.0 h
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 locallyCheck whether your project pulls in CVE-2026-55012 — 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-2026-55012 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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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.
- 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