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.
Quick 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
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.
Why can this risk appear in multiple categories?
A vulnerability can belong to more than one platform or ecosystem. Fixnx keeps one canonical risk page while also listing it in every relevant category.