Threats / Microsoft / CVE-2009-1537
CVE-2009-1537
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-08-04
Microsoft DirectX vulnerability
Microsoft DirectX QuickTime Movie Parser Filter in quartz.dll contains a NULL byte overwrite vulnerability allowing remote code execution via crafted QuickTime media files.
Verdict
Today item — known-exploited.
Remote attackers can execute arbitrary code by delivering malicious QuickTime files to systems with vulnerable DirectX components. The vulnerability has been observed in active exploitation.
CISA KEV Yes · 2026-05-204EPSS 0.51207 (verify live)5CVSS 8.8 (CISA)3CISA SSVC Exploitation: active · Automatable: no · Impact: total3
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
3 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-05-20).
Probability (EPSS)
EPSS 0.51207 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
CVSS 8.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H) · Affected: Microsoft, DirectX. Confirm exact fixed builds in the vendor advisory.CVSS — CISA-assigned via the ADP container (CVE.org), version 3.1; the CNA left no metrics, so CISA's own score is used ahead of NVD.
CISA SSVC (triage disposition)
Exploitation: active · Automatable: no · Technical Impact: totalCISA's own stakeholder-specific triage inputs, published in the CVE record (CISA Coordinator role). NOTE: this is CISA's three decision points; the final Act/Attend/Track decision also requires a Mission & Well-being input not published here, so no overall decision is asserted.
Currency of the record
CISA added this to its KEV catalog 6200 days after the CVE record was published.KEV lag = CISA-KEV dateAdded − CVE.org datePublished; a floor on how long the known-exploited flaw sat in the public record before the federal catalog listed it. Severity/weakness here is CNA- or CISA-assigned (current at disclosure), independent of NVD's analysis backlog.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
Craft a malicious QuickTime media file with NULL byte overwrite payload targeting quartz.dll
Business
Attacker gains code execution capability on victim systems
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
Distribute the crafted file via email, web hosting, or media sharing platforms
Business
Victim opens file triggering automatic parsing by DirectShow filter
3
Lateral reach — past segmentation narrative 3
Attacker
Execute arbitrary code with privileges of the user opening the file
Business
System compromise, data theft, malware installation, or lateral movement within network
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05