CVE-2022-21977: Windows 10 Information Disclosure Flaw

CVE-2022-21977 Overview

CVE-2022-21977 is an information disclosure vulnerability in the Microsoft Windows Media Foundation framework. Microsoft published the advisory on March 9, 2022, as part of its monthly security update cycle. The flaw affects supported releases of Windows 10, Windows 11, Windows 8.1, Windows RT 8.1, and Windows Server versions from 2012 R2 through 2022.

Exploitation requires local access and user interaction. A successful attack discloses limited memory contents from the targeted process. The vulnerability does not affect integrity or availability, and no public proof-of-concept or in-the-wild exploitation has been reported.

Critical Impact
Local, low-privilege attackers can trick a user into opening crafted media content to leak limited information from Windows Media Foundation memory.

Affected Products

Microsoft Windows 10 (including 1607, 1809, 1909, 20H2, 21H1, 21H2)
Microsoft Windows 11 (x64 and ARM64), Windows 8.1, and Windows RT 8.1
Microsoft Windows Server 2012 R2, Server 2016, Server 2019, Server 2022, and Server 20H2

Discovery Timeline

2022-03-09 - Microsoft releases security update for CVE-2022-21977
2022-03-09 - CVE-2022-21977 published to NVD
2024-11-21 - Last updated in NVD database

Technical Details for CVE-2022-21977

Vulnerability Analysis

The flaw resides in Windows Media Foundation, the multimedia platform that handles audio and video processing on Windows. Media Foundation parses container formats and codec streams across many user-mode and kernel-mode components.

When the affected component processes a crafted media file or stream, it exposes uninitialized or out-of-scope memory to the requesting process. The disclosed data is limited in scope, and the attack does not modify system state or crash the service. Microsoft classifies the impact as confidentiality-only with no integrity or availability effect.

The CWE classification is recorded as NVD-CWE-noinfo because Microsoft has not published component-level root cause analysis. The EPSS score is approximately 1.02% with a 77.4 percentile, indicating low expected exploitation probability.

Root Cause

Microsoft has not disclosed the specific code path or function responsible for the disclosure. Media Foundation information disclosure issues historically stem from improper initialization of buffers, out-of-bounds reads during demuxing or codec parsing, or insufficient validation of container metadata before copying it into application-accessible structures.

Attack Vector

The attack vector is local with required user interaction. An attacker must deliver a crafted media file to the victim and persuade them to open it with an application backed by Media Foundation, such as a media player, browser plugin, or document viewer that embeds video playback. Remote exploitation through network protocols is not in scope for this CVE.

No verified exploitation code is publicly available. The vulnerability mechanism is described in prose only. Refer to the Microsoft Security Update Guide for CVE-2022-21977 for vendor details.

Detection Methods for CVE-2022-21977

Indicators of Compromise

Unexpected media files (.mp4, .wmv, .avi, .mkv) delivered via email, chat, or removable media and opened by interactive users.
Crash or anomalous memory access events generated by processes that load mf.dll, mfplat.dll, or mfreadwrite.dll.
Endpoint telemetry showing media playback applications spawning unusual child processes shortly after opening untrusted content.

Detection Strategies

Hunt for Media Foundation component loads inside non-media host processes such as Office applications or scripting engines.
Correlate file write events of media containers from untrusted locations (%TEMP%, browser download paths) with subsequent media playback execution.
Monitor Windows Error Reporting and Application event logs for faulting modules associated with Media Foundation libraries.

Monitoring Recommendations

Ingest endpoint process, module load, and file event telemetry into a central analytics platform to baseline Media Foundation usage.
Track patch compliance for the March 2022 Patch Tuesday update across all affected Windows builds.
Alert on inbound email attachments and downloads of media containers from low-reputation senders or domains.

How to Mitigate CVE-2022-21977

Immediate Actions Required

Apply the March 2022 Microsoft cumulative security update for every affected Windows 10, Windows 11, and Windows Server build in the environment.
Verify patch deployment using Windows Update for Business, WSUS, or Microsoft Endpoint Configuration Manager reporting.
Prioritize patching on multi-user systems such as Remote Desktop Services hosts where untrusted users can supply media content.

Patch Information

Microsoft addressed CVE-2022-21977 in the March 9, 2022 security update. Administrators should consult the Microsoft Security Update Guide for CVE-2022-21977 to identify the correct KB article for each Windows build and install the corresponding cumulative update.

Workarounds

Restrict opening of media files originating from untrusted sources until the cumulative update is installed.
Use application control policies such as Windows Defender Application Control or AppLocker to limit which applications can invoke Media Foundation.
Block delivery of unsolicited media attachments at the email gateway and enforce SmartScreen or equivalent download reputation checks in browsers.

bash

# Verify the March 2022 cumulative update is installed on a Windows host
Get-HotFix | Where-Object { $_.InstalledOn -ge (Get-Date '2022-03-09') } | Sort-Object InstalledOn