CVE-2009-1537 — Microsoft DirectX NULL Byte Overwrite Vulnerability
Overview
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.
Vulnerability details
- CVE ID
- CVE-2009-1537
- Vulnerability
- Microsoft DirectX NULL Byte Overwrite Vulnerability
- Vendor
- Microsoft
- Affected products
- Microsoft: DirectX
- Severity
- HIGH
- Exploitation status
- Actively exploited in the wild (CISA KEV)
- EPSS score
- 50.9% probability of exploitation in 30 days · 99th percentile
- Published
- 2026-05-20
Remediation guidance
CVE-2009-1537 is in CISA's Known Exploited Vulnerabilities (KEV) catalog — U.S. federal civilian agencies are required to remediate it under Binding Operational Directive 22-01. Treat it as a priority for every environment.
Apply the vendor's official security update for Microsoft the affected product as soon as possible. Where a patch is unavailable, apply vendor mitigations or isolate/segment exposed systems.
FIRST EPSS estimates a 50.9% probability that CVE-2009-1537 will be exploited within the next 30 days (99th percentile of all CVEs) — useful for risk-based patch sequencing.
Hunt for indicators of compromise tied to this vulnerability and confirm logging/EDR coverage on affected assets.
Authoritative references
Remediate CVE-2009-1537 — and stay ahead of the next one
CVE-2009-1537 is listed in the CISA KEV catalog as actively exploited — treat remediation as urgent. Scan your domain free to see whether CVE-2009-1537 and other Microsoft issues affect you and get a prioritized remediation report (full report from ₹999) — or stream the full feed of 1,600+ actively-exploited CVEs straight into your SOC.
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