Zero-Day & Known Exploit Signature • QuickSand v2.3.0

Detecting CVE-2026-21509 in Malicious Documents & Streams

Summary: security feature bypass CVE-2026-21509. QuickSand unpacks nested container streams (OLE2, OOXML, RTF, PDF filter chains, and archives) in memory to detect CVE-2026-21509 payloads in <50ms.

CVE-2026-21509 Vulnerability Identifier

T1203, T1204.002 MITRE ATT&CK Technique

EXPLOITS Target Stream Vector

QuickSand YARA Signatures for CVE-2026-21509

YARA Rule Identifier	Stream Detection Description	MITRE ATT&CK	Engine Module	Severity
`exploit_cve_2026_21509`	security feature bypass CVE-2026-21509	T1203, T1204.002	EXPLOITS	10/10

Scan Files for CVE-2026-21509 via REST API (<100ms)

Block weaponized uploads exploiting CVE-2026-21509 in your web app, S3/GCS bucket, or SOAR phishing workflow:

curl -X POST "https://malwaretracker-912661936520.europe-west1.run.app/v1/scan?store=false" \
  -H "X-API-Key: mt_live_YOUR_API_KEY" \
  -F "file=@untrusted_document.doc"

Get Free API Key (1,000 Scans/Mo) → Scan a File Online Now

Detecting CVE-2026-21509 in Malicious Documents & Streams

QuickSand YARA Signatures for CVE-2026-21509

Scan Files for CVE-2026-21509 via REST API (<100ms)

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