Microsoft DirectX NULL Byte Overwrite Vulnerability
Microsoft DirectX contains a NULL byte overwrite vulnerability in the QuickTime Movie Parser Filter in quartz.dll in DirectShow which could allow remote attackers to execute arbitrary code via a crafted QuickTime media file.
Browse Microsoft security risksQuick answer
Microsoft DirectX should be reviewed and updated if it matches the affected versions. The recommended fix is to apply the vendor-supported patched version or the mitigation steps below, then retest the public website with Fixnx.
Who is affected
Affected versions
- 7.0
- 7.0a
- 7.1
- 8.1
- 8.1b
- 9.0
- 9.0a
- 9.0b
- 9.0c
- -
Fixed versions
- Apply the latest vendor-supported patched version.
How to fix it
Apply the Microsoft DirectX security update for CVE-2009-1537 and remove unsupported media-handling paths. Systems that process untrusted media files should be prioritized because the vulnerability can be triggered by crafted content.
- Identify Windows systems that process untrusted video, media, Office, email, or browser-delivered content.
- Apply the Microsoft DirectX security update for CVE-2009-1537 or replace unsupported Windows versions.
- Disable automatic preview or thumbnail generation for untrusted media where legacy systems cannot be patched immediately.
- Block untrusted media attachments and downloads at email, proxy, and endpoint controls.
- Restrict users on legacy systems to least privilege and remove direct internet browsing access.
- Segment machines that must continue processing untrusted media until the update is verified.
- Investigate suspicious media-file execution, crashes, or unexpected child processes from media players and preview handlers.
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Verify the fix
- Validate the Microsoft update is installed through endpoint inventory or Windows update reporting.
- Confirm unsupported Windows builds have been removed or isolated from untrusted content paths.
- Review EDR and crash telemetry for suspicious media parsing activity.
- Test normal media workflows after patching to ensure no business-critical functionality broke.
- Run a Fixnx scan to confirm no public-facing workflow instructs users to rely on vulnerable media handling.
Related categories
Related security risks
More published guidance from the same primary category.
Trusted references
FAQ
What is affected by CVE-2009-1537?
Microsoft DirectX versions listed as affected should be reviewed: 7.0, 7.0a, 7.1, 8.1, 8.1b, 9.0, 9.0a, 9.0b, 9.0c, -.
What should I fix first?
Start with internet-facing sites, admin panels, login flows, plugins, themes, modules, packages, and systems that process user-controlled input or sensitive data.
How do I confirm the fix worked?
Apply the patched version or mitigation, clear caches where relevant, retest the affected workflow, and run a new Fixnx scan to verify public website exposure signals.
How are Fixnx security risk categories chosen?
Fixnx keeps one canonical risk page and assigns only broad, relevant categories such as ecosystem, technology area, or vulnerability class.