Unauthenticated code execution via RMCAST use-after-free
Published Sep 8, 2026 · Updated Sep 9, 2026
Use-after-free in Microsoft's RMCAST driver on affected Windows releases allows remote attackers to execute code through network traffic. Microsoft identifies the memory-lifetime error in the Reliable Multicast Transport Driver but has not disclosed the specific routine, packet field, or object sequence that frees and later reuses memory. No authentication or user interaction is required, although exploitation has high complexity; successful exploitation executes code on the target system.
Summary
What happened
Use-after-free in Microsoft's RMCAST driver on affected Windows releases allows remote attackers to execute code through network traffic. Microsoft identifies the memory-lifetime error in the Reliable Multicast Transport Driver but has not disclosed the specific routine, packet field, or object sequence that frees and later reuses memory. No authentication or user interaction is required, although exploitation has high complexity; successful exploitation executes code on the target system.
The record
- CVE
- CVE-2026-69530
- Published
- Sep 8, 2026
- Updated
- Sep 9, 2026
- Vendor
- Microsoft
- Product
- Windows Server 2019
- Classifications
- CWE-416, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 8, 2026CVE publishedPublication date reported by the CVE source.
- Sep 9, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=10.0.17763.0 <10.0.17763.9245
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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