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Microsoft Management Console Mark-of-the-Web Bypass Elevation of Privilege

IdentifiersCVE-2026-27914CWE-284· Improper Access Control

CVE-2026-27914 is an improper access control elevation-of-privilege vulnerability in Microsoft Management Console (mmc.exe). According to the provided content, pre-patch builds of mmc.exe would open .msc console files without consulting the file's Mark-of-the-Web (MOTW) trust state. Patch analysis indicates the fix in KB5083768 added _IsFileSourceUntrustworthy checks in CAMCDoc::ScOnOpenDocument and extended DisplayFileOpenError to present a dedicated error for untrusted-source failures. The described exploitation path is that MMC parses the .msc XML, can instantiate CLSIDs from <SnapinCache> via CoCreateInstance, and COM activation then resolves HKLM\SOFTWARE\Classes\CLSID{...}\InprocServer32 and loads the referenced DLL into mmc.exe. In the reported lab scenario, a low-privileged user planted a MOTW-tagged .msc file in a world-readable location; when an administrator opened it on a pre-patch system, mmc.exe loaded an attacker-controlled DLL and executed code inside a High Integrity MMC process, crossing a Medium Integrity to High Integrity boundary.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows a local authorized attacker to elevate privileges by causing a higher-privileged user to open a malicious .msc file on a vulnerable system. The provided content states this can result in execution of attacker-controlled code inside elevated mmc.exe and that Microsoft assessed the issue as potentially leading to SYSTEM privileges. This creates high impact to confidentiality, integrity, and availability, including arbitrary code execution in a high-integrity context, privileged process abuse, and follow-on actions such as spawning processes or modifying the system with elevated rights.

Mitigation

If you can’t patch tonight, do this now.

Until patching is complete, restrict or monitor opening of .msc files from untrusted locations, especially files carrying Zone.Identifier/ZoneId=3 Mark-of-the-Web metadata from Downloads or shared writable paths such as C:\Users\Public. Hunt for mmc.exe opening MOTW-tagged .msc files and audit HKLM CLSID InprocServer32 registrations that resolve to non-system, world-readable, or user-writable DLL paths, since the described chain relies on COM snap-in activation loading a DLL into mmc.exe. Limit administrative use of untrusted console files and avoid opening externally sourced .msc files on privileged sessions.

Remediation

Patch, then assume compromise.

Apply Microsoft's security update KB5083768, which modifies mmc.exe to reject untrustworthy .msc sources by adding _IsFileSourceUntrustworthy checks in CAMCDoc::ScOnOpenDocument and associated user-facing error handling. Ensure affected Microsoft Management Console binaries are updated to the patched version across endpoints and administrative workstations.
PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
Microsoft CorporationManagement Consoleapplication
Microsoft CorporationWindows 10 1607operating_system
Microsoft CorporationWindows 10 1809operating_system
Microsoft CorporationWindows 10 21h2operating_system
Microsoft CorporationWindows 10 22h2operating_system
Microsoft CorporationWindows 11 23h2operating_system
Microsoft CorporationWindows 11 24h2operating_system
Microsoft CorporationWindows 11 25h2operating_system
Microsoft CorporationWindows 11 26h1operating_system
Microsoft CorporationWindows Server 2012operating_system
Microsoft CorporationWindows Server 2012 R2operating_system
Microsoft CorporationWindows Server 2016operating_system
Microsoft CorporationWindows Server 2019operating_system
Microsoft CorporationWindows Server 2022operating_system
Microsoft CorporationWindows Server 2022 23h2operating_system
Microsoft CorporationWindows Server 2025operating_system
Microsoft CorporationWindows Server 23h2operating_system

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

What this page doesn’t show

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Exposure mapping

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Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures1

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity6

Community discussion across Reddit, Mastodon, and other social sources.

Microsoft Management Console Mark-of-the-Web Bypass Elevation of Privilege (CVE-2026-27914) | Mallory